Scoob! (Alternate extended version)

Scoob! is an American computer-animated supernatural, adventure comedy mystery film featuring characters from the Scooby-Doo franchise, produced by the Warner Animation Group and distributed by Warner Bros. Pictures. The film is directed by Tony Cervone from a screenplay by Kelly Fremon Craig and a story by Matt Lieberman, and stars the voices of: Will Forte (who, as the title character, is the only member of the original cast to reprise his role), Mark Wahlberg, Jason Isaacs, Gina Rodriguez, Zac Efron, Amanda Seyfried, Kiersey Clemons, Ken Jeong, Tracy Morgan and Frank Welker as the Scooby gang. It also has the voices of: Iain Armitage, Mckenna Grace, Pierce Gagnon, Ariana Greenblatt, Simon Cowell, Christiana Hendricks and Henry Winkler. It is a reboot of the Scooby-Doo film series, and is intended to be the first film of a proposed set up for a Hanna-Barbera Cinematic Universe. The film's story follows the formation of Mystery Incorporated, and how they are then joined by Dynomutt and Blue Falcon, Speed Buggy and his pitcrew, Jabberjaw and the Neptunes and other well-known characters to solve their most challenging mystery related to the origin and the true purpose of their own mascot in conjunction with Dick Dastardly's plot to unleash Cerberus, a monstrous three-headed ghost dog, upon the world. This version features content that was cut from the film due to time. Added content, cast and characters and extended run time. It's rune time is 122 minutes.

Promise
Mystery Inc. rally other heroes to prevent a dogpocalypse from being unleashed, which will bring about the release of the ghost of Cerberus, and a secret history behind Mystery Inc.'s mascot, Scooby-Doo. Meanwhile, supervillain Dick Dastardly attempts to steal treasure from the Underworld.

Synopsis
At Venice Beach, California, an unmanned, stray puppy is wandering the streets looking for food. He comes across a restaurant, Alexander's Great Gyros, and sees a giant piece of meat hanging in the window. Seeing as how the meat was unclaimed, the puppy thinks nothing of picking it up and stealing it.

The shop owner calls out as his meat is being stolen and a cop starts pursuing the puppy. In the midst of the pursuit, the puppy bumps into a young boy, Shaggy, who is walking by himself to the beach. However, the puppy keeps on running away from the cop, paying little regard to Shaggy.

Shaggy plugs in earbuds and begins listening to music on his phone. The song he is listening to is about loneliness, so he changes the music station. The next song is also about loneliness, so he changes the music station again. This continues on for a few songs until he gives up and begins listening to a podcast, only to find out that it is about loneliness.

After a long chase, the puppy eventually escapes the cop by hiding behind two mounds of sand. Shaggy then comes up to the mounds of sand, unaware of the puppy's presence, and sets up a picnic, pretending that the mounds of sand were his friends.

The puppy starts to feel empathetic towards Shaggy and comes out from behind the sand, offering to eat with Shaggy. When Shaggy explains that while he has a sandwich to share but that it doesn't contain any meat, the puppy brings out the stolen piece of gyro meat and cuts slices for the sandwich.

The cop finally finds Shaggy and the puppy and insists that "this mangy stray is coming with me." Shaggy refuses and claims that the puppy is his dog and that his name is Snacks. When the cop doesn't believe the name, Shaggy corrects himself and says that his name is Scooby-Dooby-Doo. The cop then lets them be, as the law is that dogs with middle names can't be arrested. Shaggy tells the puppy, now named Scooby, that he can be his dog if he liked. Scooby agrees and they head home to Shaggy's house.

Once at home, Shaggy shows Scooby his room, which is filled with memorabilia of Blue Falcon and Dynomutt, Shaggy's favorite superheroes. Shaggy then gives Scooby a gift, a custom collar for him, which Scooby bows to never take off.

On Halloween night, Shaggy and Scooby, dressed up as Blue Falcon and Dynomutt, go out trick-or-treating. They come to the Rigby House, a mansion that Shaggy claims is haunted. They begin to walk away when two bullies steal their bag of candy and throw it into the Rigby House. After the bullies run away, Shaggy and Scooby meet Fred, Daphne, and Velma, a group of friends, who want to make sure they're okay after being picked on. They offer to go into the house and try to get their candy back.

When they walk into the house they are attacked by a ghost who chases them around. During the commotion, Velma notices that the ghost is attached to a moving wire system in the ceiling. Fred cuts the wire with an ax that was hanging on the wall and the ghost falls down, only to be tied up by Daphne and Velma, and attacked by Fred.

Upon looking more carefully at the ghost they discover that he isn't a ghost and is actually Mr. Rigby, wearing a mask. Shaggy and Scooby discover a secret hidden room, filled to the brim with expensive, stolen electronics. The police arrive and take away Mr. Rigby. The five friends, happy with their success in stopping a crime decide to pursue mystery solving.

A montage ensues in which the gang solves a variety of cases and takedown classic monsters from Where Are You. Throughout the montage, they transition into young adults.

Fast forward to years later in Machu Picchu, Peru, two archeologists Dr. Fitzhugh and Sandra found a giant-sized canine skull which they both believed that it belonged to mythical three-headed dog, Cerberus, the guardian to the gates of the Underworld. Sandra couldn't understand how one of the skulls end up in Peru to begin with. Fitzhugh showed Sandra murals on the walls that the skulls were separated and hidden across the world in three mythical places. And according to the legend, that if the three skulls were ever to be reunited, the gates of Hades would rise again and plunge the world to darkness.

Sandra was confused of why would any one want that to happen. Fitzhugh then acts very strange all of a sudden and tells her that behind the gates, lies an enormous treasure horde which would make him the wealthiest man in history and he then pulls a weapon from his sleeve and aims it at her. Dr. Fitzhugh unmasks himself as Dick Dastardly and Sandra presses the alarm button but no sound was heard as the alarms were already disabled and the security guards are incapacitated by Dastardly's devious henchwoman, Pandora Pitstop. Dick shoots a sticky substance at Sandra that sticks her to the wall.

Sandra struggles and tells him the skulls are useless without a certain key. However Dick assures her that the prophecy is already been fulfilled and knows where to find it. After an awkward moment with one of his robots, Dusty, Dastardly signals his giant air ship, the Mean Machine and drops one of the claws onto the skull and Dastardly, Pandora and Dusty hop on as the claws lifts up the skull. Dick then chants the skull to where the other two are hidden then it projects green beams of supernatural light and circles around the area then stops to the pointed direction. After getting a set of coordinates, Dastardly bids Sandra farewell who warns him that Blue Falcon will stop his plan as he make his departure to search the remaining skulls and the key.

Few months later in Venice Beach, Scooby and the gang is eating at a diner, contemplating what 's next for mystery will be. Fred, Velma, and Daphne are all ready to make Mystery Inc. a real business. Velma explains that they require money to take on bigger cases; scarier villains and creepier mysteries. Simon Cowell, the celebrity television host and entrepreneur, is considering to be their possible investor. Cowell shows up to the diner and explains that for him to invest in Mystery Inc. they need to be a better group for Fred is the muscle, Daphne is the empath and Velma is the brains. He says that Shaggy and Scooby aren't pulling their weight and that they add nothing dynamic of the team. Simon couldn't invest Mystery Inc. as long Shaggy and Scooby-Doo are involved; claiming that friendship won't save the day.

Feeling abandoned and heartbroken by Simons words, Scooby and Shaggy leave the diner despite Velma, Daphne and Fred's pleas. The two then went to the Takamoto Bowl, a bowling alley where they usually hang and cool off. Scooby knocks down all of the bowling pins but one in his first shot. He knocks down the second one, but it jumps back up as if it was alive. Suddenly, a pair of red eyes appear in the bowling pin, but before Scooby can show Shaggy, they disappear. Scooby waits for his ball to come back in the ball return. When it doesn't come back for a while, they start to suspect that something is off.

Suddenly, the bowling pins and balls transform into little robots! They begin firing lasers at Shaggy and Scooby, who slide down a bowling lane to escape them. They pretend to be cashiers, working at the bowling alley, and try to take food orders from the robots. But the robots catch on to their charade and start chasing them again.

While this is going on, Fred, Velma, and Daphne get an alert that there are robots attacking the bowling alley. Remembering that Shaggy and Scooby like to go there, they fear that their friends are in trouble and rush over to help them.

Shaggy and Scooby go into an alley behind to bowling alley and run into a dead end. They are about to be caught by the robots when all of a sudden a blue light beams them up into the sky. They are inside the interior of a futuristic airplane. Upon looking around, Shaggy realizes that they are inside the Falcon Fury, Blue Falcon's airship. The two are welcomed by the Teen Angels; Dee Dee Skyes, who is the pilot of the Falcon Fury, Taffy Dare, who is the engineer of Falcon Fury and Brenda Chance, the nervous confidant of the Falcon Fury.

Dee Dee explains that the robots were sent by the supervillain Dick Dastardly who seemingly wants to kill Shaggy and Scooby, although she, Taffy and Brenda do not yet know why he wants to do so. They arrive at the center of the ship, where Blue Falcon makes an entrance.

While Shaggy and Scooby are initially excited to see Blue Falcon, they are confused, as he looks very different. Dynomutt appears and reveals that actually, he is the son of the original Blue Falcon, Brian Crown, and that he has taken over the position of being a superhero. Brian, now the new Blue Falcon, explains that his father, Radley Crown is now retired to Palm Beach. While Dynomutt on the other hand still misses him dearly.

All at once, an alarm goes off in the ship alerting that Dick Dastardly is close by. Dee Dee explains that he tracked Shaggy and Scooby from the bowling alley. They all run up to the helm of the ship, the Falcon Nest and a chase ensues!

Dastardly orders the robots, who he calls Rottens, to attack the Falcon Fury. He explains to them that if he doesn't get to the ship he'll never get his "treasure."

Inside the Falcon Fury, Dynomutt, Blue Falcon, and Teen Angels explain to Shaggy and Scooby that Dastardly is collecting the skulls of Cerberus, although they still don't know what they have to do with Shaggy and Scooby, or why Dastardly wants them. They reveal that Dastardly already has one and that if they don't stop him, he'll get the other two. Their mission is to collect them before he can.

The Mean Machine latches onto the Falcon Fury using harpoons and is about to drag it in when Brenda had and idea then tells Dynomutt to reverse the polarity of the tractor beam, so that it pushes them away from the Mean Machine. Dee Dee thanks Brenda for the idea but tell her that next time they're in trouble, she handle it. They head back to the center of the ship, and Dynomutt comes to the conclusion that actually Dastardly wants Shaggy and Scooby alive, as he could have killed them earlier instead of just trying to capture them. Blue Falcon then says that Shaggy and Scooby are important, though they still don't know why, and that they'll need their help on their mission. Shaggy is reluctant to agree, as he still feels like the "weak link," but Scooby talks and convinces him into joining as a chance to prove Simon Cowell wrong.

Meanwhile, back at Takamoto Bowl, Fred, Velma, and Daphne are asking questions to the owner, Judy Takamoto to figure out what happened to Shaggy and Scooby. They feel guilty for their disappearance, as they made them feel unwanted. When inquiring about the robots, Judy hands them a cardboard box with the remains of one of the Rottens.

Back in the Mystery Machine, Fred, Daphne, and Velma investigate the Rotten. They discover a loose hair on the robot and track it back to Dastardly Demolition, previously owned by Dick Dastardly. They find out that along with the footage of stealing the first skull of Cerberus he's also been stealing the genealogical records of many dogs from the Canine Global Kennel Club. They decide to go after him and help Shaggy and Scooby and they drive off.

At the Falcon Fury, Dee Dee and Dynomutt are searching for the second skull by locating areas with high fossil density. Blue Falcon, on the other hand, is trying to find the skull by asking his social media followers if they know where it is. Taffy is repairing the damages done to the Falcon Fury's wings. Shaggy and Scooby come in, their hands full of food. They prepare a "Scoob-Shag Specialty," ice cream and a jalapeño pepper. Thanks to an idea from Shaggy and Scooby, Dee Dee and Dynomutt figure out that the second skull is in the Gobi Desert by tracking it's supernatural heat signature and they urge Blue Falcon to go there with them. However, Blue Falcon decides instead to listen to a DM that says that the skull is in an abandoned amusement park in Romania.

Meanwhile, in the Mystery Machine, Velma reveals that by cross-matching the biographical data that Dastardly stole, she is able to determine and discovered that Scooby is the last descendant of Peritas, the dog of Alexander the Great. Daphne makes the point to Fred and Velma that this is "our most important mystery ever," as it involves Scooby. Fred changes course, as he claims he "knows a shortcut."

However he notice that the Mystery Machine is running low on gas and drives to the Service Gas station next to them. As Fred refuels the Mystery Machine he quickly notices an orange Dun buggy behind him and comments on the tires and the car speaks and thanks him for the compliment. This freaks out Fred alerting Velma and Daphne, followed by three other teens exiting the store. They introduced themselves to the gang as the Speed Bugs; Mark, the pit crewman with fellow pitcrewwoman and friend Debbie, their driver Tinker and their mascot Speed Buggy.

The three already familiar with Mystery Inc. but Debbie notices that Shaggy and Scooby aren't with them. Velma tells them that it's long story and that they were on their way to Dastardly Demolitions, which the Speed Bugs have been there many times to collect spare auto parts for Speed Buggy and they ask to join Mystery Inc to save their friends as they like to solve mysteries and stopping villains. Mark already knows a quicker route while Velma can tell him, Debbie, Tinker and Speed Buggy everything she knows along the way. As they start to drive off, the Rotten, unbeknown to them, reactivates again.

The Falcon Fury arrives at Funland, the abandoned amusement park in Romania. As soon as they walk inside the park, the Mean Machine ascends from the sky. Dastardly and the Rottens fly down and Dastardly reveals that he was the one who sent Blue Falcon the DM and that he has just retrieved the second skull from the Gobi Desert.

Dynomutt offers to help them fight Dastardly but everyone runs away. The Rottens chase Shaggy and Scooby into an arcade, full of references and posters to other Hanna-Barbera characters. They play "whack-a-mole" with the Rottens, trying to destroy them. Dastardly breaks into the arcade and when Shaggy asks what he wants with him, Dastardly reveals that Shaggy isn't important at all and that he only wants Scooby.

Dastardly shoots Shaggy out of the arcade and he falls into a Ferris wheel seat where Blue Falcon happens to be hiding, although he claims that it is a "superior vantage point."

Scooby escapes the arcade and ventures into a house of mirrors, where Dastardly is waiting for him. Dastardly tells Scooby that if they join forces, he could make him "the most important dog in the world." He explains that Scooby is the key to something very important. Scooby refuses to help Dastardly and runs out of the house of mirrors, where more chaos is happening.

Shaggy and Blue Falcon deploy a Falcon bomb that detaches the Ferris wheel from the ground and sends them flying into an mysterious race car that is driven by famous racer, Penelope Pitstop much to Pandora's disgust! Dynomutt and Scooby jump into the car as well, after being chased by Dastardly on bumpy cars while Pandora is driving her updated racing vehicle on a race track. Dee Dee deploys the tractor beam, which beams them all up into the Falcon Fury, leaving Dastardly and Pandora to fall many feet into the ground. He is then alerted by the Rotten in the Mystery Machine of the existence of Fred, Daphne, Velma and the Speed Bugs. Pandora indicates that they are enroute to Dastardly Demolitions.

Back in the Falcon Fury, Blue Falcon is excited to hear that Dastardly finds Scooby so important. Penelope Pitstop introduced herself to the Falcon Force and she reveal to them that she's been tracking down Dick Dastardly for months after he stole the first skull in Peru. Blue Falcon welcomes her aboard and decides that Scooby should have a super-suit so that he fits in with them. In the process of getting his suit, he has to take off his collar, something he vowed to never do. Shaggy walks away, feeling alone. When Blue Falcon goes to try to comfort Shaggy, Shaggy points out that they aren't too dissimilar, as Blue Falcon doesn't fit in because he's not like his father.

Brenda comforts Shaggy as well that she understands how he feels of what it means less important after she, Dee Dee and Taffy joined with Brian and Dynomutt. Penelope shares the same pity and reveals to Shaggy and the Teen Angels that Pandora is her younger twin sister.

On the road Fred, Daphne, and Velma, in the Mystery Machine, driving with the Speed Bugs reminisce about the good times they had with Shaggy and Scooby. They, Mark, Debbie, and Tinker, in Speed Buggy see a broken down tour bus which they all stop to check what's going on. They meet the famous rock music band, the Neptunes; Biff Starke, Shelly LaMarine, Bubbles Blowton, Clamhead and their drummer/mascot, a friendly talking 15ft.Great white shark Jabberjaw. Biff explains to the gang and Speed Bugs that they're off season for some down time after their monthly tour for down time. Mark and Debbie fixed their tour buss which as actually a Hoverbuss acquired by Dr. Benton Quest.

Biff thanks them for the repairs and Clamhead asks if there's any way at all they can repay them, Velma ask if they've ever been to Dastardly Demolitions. Bubbles notice that Shaggy and Scooby are missing. After the gang brings them up to speed, the Neptunes offered to join them to save their friends and stop Dick Dastardly for they also love to solve mysteries and catching villains. Shelly disagrees and states that this is not their business but Biff convinces his girlfriend that they've always get into situations that didn't involve them all the time and Mystery Inc. would've done the same for them if Jabberjaw and Clamhead would've been kidnapped and Shelly agrees to come along. The Neptunes came along with them in their hovercar, the Neptunemobile.

They all arrive at Dastardly Demolitions but know one appears to be home as Debbie and Mark talked to Velma that it's been abandoned for years after Dick Dastardly started his supervillain career. There's a slim chance of Shaggy and Scooby being held captive here. Refusing to give up on their friends, Fred, Daphne, and Velma reminisce about the good times they had with Shaggy and Scooby again. Then they here something amongst the junkpile, then notice an anthropomorphic dog named Penrod Pooch appears and greets the young teens. He introduced them as a freelance janitor that but has no clue of where Scooby and Shaggy are.

Velma and Shelly simultaneously find out, by looking at a social media post, they discover that Scooby and Shaggy are with Blue Falcon. Suddenly, a cop car arrives and Penrod sneaks away and jumps into a filling cabinet but gets stuck. It is love at first sight when Fred (and Mark) sees the cop, as they finds her extremely attractive. The cop, however, turns out to be Dastardly in disguise and he deploys his Rottens but were halted by the surprising appearance of the masked canine Kung Fu hero Hong Kong Phooey after being freed by Spot. He fought off the Rottens but was hit with a tranquilizer by Pandora Pitstop from behind. to capture and pull Velma, Fred, Daphne, Mark, Debbie, Tinker, Speed Buggy, Biff, Shelly, Bubbles, Clamhead and an unconscious Hong Kong Phooey up into the Mean Machine along with their Mystery Machine and the Neptune's hover car and locks them all in two cells. While Speed Buggy is help up and Jabberjaw trapped in a giant fishbowl.

Dusty, the Rotten with the vacuum head, walks by their cells, then was kicked and taunted by Pandora Pitstop and later then taunted Mystery Inc., Speed Bugs and the Neptunes. Blast-Off Buzzard, nick named Bob flies in from the window with blue prints which he had stolen from QuestLabs while having few days off before getting back. Hong Kong Phooey shortly regains consciousness. After they both left to the reveal of the final skull of Cerberus, Daphne persuades Dusty to let them out of the cages after cleaning out the dust in his head. They sneak to the center of the Mean Machine, where they spy on Dastardly, who is using the two skulls of Cerberus to reveal that the third is hidden in a place called Messick Mountain.

Dusty points them to a room with a communications device. Velma hacks into Dynomutt, telling Dee Dee, Taffy and Brenda that the third skull is at Messick Mountain. In the room, they lost the signal to the Falcon Fury and find a pinboard, revealing Dastardly's plans for Scooby and the Skulls of Cerberus. They learn that Scooby, being the descendant of Peritas, is the only one who can unlock the gates to the Underworld, where Alexander the Great hid his enormous treasure. They also find a shrine display shelf of Muttley's belongings.

Dastardly breaks in, catching them. He reveals that Muttley is stuck in the Underworld, having gotten trapped there after a failed portal experiment. He then commands the Rottens, Blast-Off Buzzard to take away Velma, Daphne, Mark, Debbie, Tinker, Biff, Shelly, Bubbles and Clamhead back to their cells but Dastardly keeps Fred as he has "big plans" for him

The Falcon Fury arrives at Messick Mountain, which turns out to have a Mesozoic ecosystem. Shaggy, feeling as if the Falcon Force is tearing him and Scooby apart, tells Scooby that he must choose between him and them, as he won't go with them to Messick Mountain. Scooby chooses the Falcon Fury crew, leaving Shaggy alone with Brenda choosing to stay behind to keep him company.

While investigating the landscape of Messick Mountain, Blue Falcon and Scooby run into Captain Caveman, the protector of the third skull, which he calls a Slaghoople. He takes them to an arena, filled with other cavepeople, that to get the skull, they must defeat them in battle. Meanwhile Dee Dee, Dynomutt, Taffy and Penelope had a friendly encounter Grape Ape after he protected them from a Tyrannosaurus-Rex.

Shaggy walks inside the Falcon Fury sad with Brenda following him with great concern. Shaggy picks up Scooby's collar remembers the promise that he would never leave him no matter what when he was a kid. Fred, shows up to the Falcon Fury, alone in the Mystery Machine. He tells Shaggy that they need to go to Scooby, as he's in great danger that Dastardly is already on his way to Messick Mountain.

Captain Caveman starts to battle with Scooby and Blue Falcon, overpowering them immensely, and even destroying Scooby's super-suit. Dee Dee, Taffy, Penelope and Dynomutt show up with Grape Ape's aid to help and Dynomutt knocks Captain Caveman into a wall, beating him. Fred, Shaggy and Brenda show up in the Mystery Machine. Fred reveals that he isn't Fred at all and is actually Dastardly in disguise. The Mean Machine appears overhead and Dastardly kidnaps Scooby and escapes with him and takes the third skull. Pandora Pitstop, Blast-Off Buzzard throw Velma, Daphne, the real Fred, Mark, Debbie, Tinker, Speed Buggy, the Neptunes, Jabberjaw and Hong Kong Phooey overboard, although some of them are caught by the members of the Falcon Force while Speed Buggy made it t the ground safely by riding the Pterodactyls, Penelope Pitstop caught Hong Kong Phooey. and both Mark and Biff simultaneously catches Shelly and Debbie. Dick Dastardly then departs from Mystery Island in the Mean Machine to Athens, Greece.

The rest of the gang, Speed Bugs, the Neptunes, Penelope, Hong Kong Phooey and the Falcon Force made their way back to the ship only to find that it has been destroyed by Dastardly. Taffy stayed behind to help Captain Caveman before catching up. Dee Dee scanned the wreckage and revealed that the primary engine is destroyed except the thrusters are intact but to small to lift the ship. Fred and Blue Falcon began to argue about blaming each other back and forth about Scooby's capture then the both started to fight. Velma, Daphne, Dee Dee, Dynomutt, Mark, Debbie, Biff, Hong Kong Phooey and Penelope try to break them up while Brenda, Tinker, Bubbles, Clamhead, Speed Buggy, Jabberjaw tried pleading and reasoning all of them to stop fighting each other, but Shaggy stops their argument and he admits that he's to blame for Scooby's capture after letting his own jealousy strain their friendship.

He admitted that he was afraid that things were going to chance between them, but acknowledges that people can grow but it doesn't mean they're growing apart and the one thing that will never change that Scooby-Doo is his best friend. Tinker steps up and relates to Shaggy for his friendship with Speed Buggy while Clamhead relates for his friendship with Jabberjaw and Branda for her friendship with Dee Dee. She confesses to her that when they join the Falcon crew, she felt that the Teen Angels were drifting apart and that if she was no longer mattered to her and Taffy. Dee Dee then hugs Brenda and tells Brenda an Taffy that they has always been like a sisters to her to since they were children and nothing will ever keep them apart as long they're together. Taffy came in as she heard everything Dee Dee said with Captain Caveman whom she kindly patched him up after he bruised his knee earlier.

Captain Caveman tells Shaggy and everyone that he wants to come with them to help for he has newfound respect for Scooby-Doo after their battle for the Slaghoople. After Shaggy gives an inspiring speech, everyone works together to reconstruct the Mystery Machine in order to return to the surface pursue Dastardly while Speed Buggy and the Neptunes hover are given boosters and Hong Kong Phooey called- n his shape-changing mode of transportation the Phooeymobile. Only the to be joined by Grape Ape who also want's to come along to help.

In Athens, Greece the Mean Machine arrives to the Parthenon where Dastardly descends the the Skulls of Cerberus and Scooby Doo with Pandora beside him and Bob flying down for a landing. Dastardly connects the skulls which summons the gates to the Underworld which supernatural turns the sky dark and restores the Parthenon to it's former state. Just as Dastardly demands Scooby for his paw, sees on his watch that the Mystery Machine in the sky, having been transformed to have wings and jets followed by the Speed Bugs, Neptunes in their hovercar, Penelope Pitstop, Hong Kong Phooey in his Phooeymobile and Grape Ape who used two Pterodactyls to fly out of Messick Mountain. Dastardly orders for them to be shot down, but Dusty purposely misfires so that Daphne's life is saved. However, the Mystery Machine, still falls to the ground, it's wings being shot off. While Speed Buggy, Pitstop, Hong Kong Phooey and the Neptunes land safely while Grape Ape releases the Pterodactyls and rushes to the Parthenon fast as he can.

Dastardly forces Scooby's paw upon the the gates, unlocking them. After the gates open, Cerberus comes through, something Dastardly was not expecting. open it, in which Cerberus escapes and begins causing havoc, something which Dastardly himself didn't expect. Horrified by this, Dastardly, Pandora and Blast-Off flees near the gate while telling Scooby and the other civilians to run away from the scene and avoid getting into Cerebus' wrath.

This created enough commotion for Scooby to run off to the Mystery Machine only to see that they, Blue Falcon, Captain Caveman and the Teen Angels have survived. The gang is finally reunited! Penelope Pitstop The Speed Bugs, the Neptunes and Hong Kong Phooey arrive to see if the gang is alright only to see that they have reunited with Scooby-Doo. With Daphne quick introductions made for Scooby-Doo, she asks if everyone's accounted for. Dynomutt also survives and emerges from the wreckage while a brokenhearted Fred looks at the burning remains of the destroyed Mystery Machine.

Dick Dastardly enters the Underworld with Pandora Pitstop and Bob following behind him. Not only they see the treasure, Dick spots Muttley who was unconscious; Dick started apologizing in a regretful way for getting him trapped in the first, only to hear his snickering and realize that Muttley's alive, caused Dastardly to bonked his companion on the head, leading the two to have a brief bickering. In spite of it, Dastardly couldn't stay mad at him and the they rejoiced. Pandora hated to spoil their "happy reunion", there still so much treasure around for themselves to bring back.

On the Parthenon Cerberus then searches for Mystery Inc., Falcon Force, Speed Bugs, the Neptunes, Penelope Pitstop and Hong Kong Phooey whom are all hiding in a building knowing that had to stop Cerberus before he gets to the city below. Fred recklessly charges at Cerberus to avenge the Mystery Machine but gets flicked away.

Scooby, Shaggy, the Falcon Fury crew, Captain Caveman, Tinker and Speed Buggy, Clamhead and Jabberjaw begin attacking Cerberus as a means to distract him while on the other hand Fred, Velma, Mark, Debbie, Biff, Shelly and Bubbles figure out how to close the gate. Brian runs away with Dynomutt going after him. Cerberus then corners Scooby, Shaggy and Daphne, The Rottens, at the command of Dusty, deploy themselves, deciding to help the gang instead of Dastardly.

Dynomutt finds Brian hiding as he attempts to call his father but he stops his call that he he doesn't need to be the same as his dad to be a good superhero. Tells him to look at Scooby and Shaggy whom both terrified and taking on Cerberus aided Tinker and Speed Buggy, Clamhead and Jabberjaw and Penelope Pitstop. This motivates and encourages him to activate his Falcon wings and help him fight.

Speed Buggy and Tinker drift around Cerberus to distract Cerberus but the two were swatted away by his tail and slammed into a wall, damaging Speed Buggy. Tinker and Clamhead check on him while Cerberus prepares to devour them both. Seeing Clamhead in danger, this toughens up Jabberjaw to bravely and ferociously bite Cerberus' tail to protect his best friend. The Teen Angles engage Cerberus in coordinative formation with Captain Caveman on the attack. This angers Cerberus further to let out an unearthly howl that summons a pack of smaller ghostly skeletal Orthrus in Greek armor which are his Avatars from the Underworld which no one never saw coming! Hong Kong Phooey, Penelope Pitstop, Captain Caveman and the Teen Angels fought off most of them.

Cerberus attempts to devour Scooby but Blue Falcon swoops in makes the save. Cerberus then viciously swats Scooby away, but was saved by Grape Ape who made it in time to help his friends as he charges and battles Cerberus.

Dick Dastardly, Muttley, Pandora Pitstop and Blast-Off Buzzard come through the gates with much of Alexander's treasure as they can get away with. At the gate Fred gives Velma the picture of the gate's lock which he had taken from the pinboard on the Mean Machine and behind it was a prophecised riddle written in ancient Greek. Velma, Daphne, Fred, Mark, Debbie, Biff, Shelly and Bubbles read the riddle: "Two brothers bridge the earthly void. One man. One dog, the key employed.  One to open., two to close. A pair whose friendship forever grows." Velma looks at the lock and reveals that it takes one to open, two to lock the gate with a catch...

Grape Ape then pushes Cerberus back to the gate with all his might and the Rottens, having transformed into bowling balls, trip his avatars, which makes them slide through the gate while Grape Ape lifts a defeated Cerberus and throws him through the gates and back to the Underworld. Everyone helps to close the gate, although it still remains unlocked. Fred, Velma, and Daphne inform Scooby and Shaggy will both need to activate the lock, although one of them will have to do it from inside the Underworld. Shaggy asks if there was another way but Velma and Mark tells him that Alexander the Great built the gates to be locked only by him and Peritas, for Scooby being his last descendent. Shaggy, in a moment of heroism, volunteers and locks himself inside the Underworld. Scooby activates the lock as well, and the gate locks and disappears, returning Parthenon back to its normal state.

Scooby Doo and everyone mourn over Shaggy. A saddened Scooby was then comforted by Fred, Daphne and Velma then joined by Jabberjaw, Speed Buggy and Captain Caveman to comfort Scooby over losing his best friend. Velma then asks if they're missing from the riddle and ponders of why Alexander builds the gates to separates him from his best friend Peritas forever. Fred suggests that he must built a way out then two statues of Alexander the Great and Peritas appear with an inscription "Our bond will never break or bend. So my friend, its time to return to your home." when suddenly a portal appears, and Shaggy is returned back to the normal world by Cerberus.

Scooby-Doo was overjoyed that Shaggy is back while the rest of the gang, Blue Falcon, Dynomutt, Teen Angels, Captain Caveman, Speed Bugs, the Neptunes and Jabberjaw, Penelope Pitstop and Hong Kong Phooey all embrace him in a big group hug with Grape Ape giving them a bigger one., Shaggy then puts Scooby's collar back on him. Velma figures out that Scooby and Shaggy are the heart of Mystery Inc. Brenda comes in and warfully hugs Shaggy hinting she may have a crush on him. Dynomutt licks Brain but minorly painfully scratch his face with the metal tongue which he should've thought through.

With his knee better again, Captain Caveman gives Taffy her bandana but she wants him to keep as a token for their friendship. Blue Falcon then welcomes Captain Caveman, Hong Kong Phooey and Grape Ape as new members of the Falcon Force for acts of bravery and heroics with the exception of Penelope Pitstop who declines the offer that's she's used racer.

Debbie realized that they all forgot about Dastardly but Dusty points out that the rest of the Rottens have captured Him, Muttley, Pandora and Bob and brings them to the gang, al tied up. They unmask Dastardly, revealing him to be Simon Cowell. Upon realizing that this makes no sense, Velma unmasks him again, revealing him to only be Dastardly who believed that no one ever falls for the double-unmasking which cause Muttley to snicker much to Dastardly chagrin. Pandora points out to Dastardly that they may not have escaped with the treasure, the bight side is that they got Muttley back which he agrees with and so does Blast-Off Buzzard. She then had brief argument with Penelope afterwards for being in her shadow for years being second best, being their father's favorite.

They are then taken into custody by Blue Falcon, Dynomutt, Teen Angels, Captain Caveman and the rest of the Falcon Force to be handed to the authorities along with impounding the Mean Machine. Dynomutt then sees Mark, Debbie and Tinker tending to the heavily damaged Speed Buggy which he and the Teen Angels promise that they can fix him for them.

Mystery Inc. made their way back to Venice Beach where they unveiled the grand-opening of their new headquarters by using some of the treasure. The Falcon Fury appears in the sky ad beams down Blue Falcon as the DJ Shaggy recommended for the party. He, Dynomutt, Dee Dee, Brenda, Taffy and Captain Caveman give the gang a new and improved Mystery Machine as an addition to their new HQ. Mark, Debbie and Tinker show up for the celebration with in newly upgraded Speed Buggy. Jabberjaw and the Neptunes arrive to sign autographs give and encore to Mystery Inc. Hong Kong Phooey, and Grape Ape followed by Penelope Pitstop join the party, as well as signing autographs to her racing fans in Venice. Tinker comments that it exciting that everyone had a daring adventure save the world from an apocalyptic threat and the next time it should happen once more someday, they should team up again. Everyone starts to party and dances to the music while Dick Dastardly, Muttley, Pandora Pitstop and Blast-Off Buzzard dance in their jail cells.

Mystery Inc. gets a call from Jaime Rivera who tells them that there have been sightings in San Pedro of a phantom tuna trawler and the ghost of a sea captain. The gang heads off in a haste, to pursue new mysteries!

In the credits, Mystery Inc.'s popularity rise through the media and they are seen consulting Dr. Benton Quest after leaving the Rottens in his care at Quest Labs with his son Johnny, Race Bannon, Hadji and Bandit. Blue Falcon and Dynomutt later recruits Atom Ant to the Falcon Force while battling with their nemesis Mr. Hyde and his Hideous Hyde Hound. Tinker and Speed Buggy participated in a Wacky Race competing with Penelope Pitstop. The Neptunes and Jabberjaw shared a performance with Josie and the Pussy Cats. Grape Ape joined a giant monster wrestling league as a part time side job and is managed by Beegle Beagle. While Muttley breaks Dastardly, Pandora and Blast-Off Buzzard out of prison.

Characters
Main Characters:
 * Mystery Inc
 * Scooby-Doo
 * Shaggy Rogers
 * Fred Jones
 * Daphne Blake
 * Velma Dinkley

Supporting Characters:
 * Blue Falcon
 * Dynomutt, Dog Wonder
 * Teen Angels
 * Dee Dee Skyes
 * Taffy Dare
 * Brenda Chance
 * Speed Bugs
 * Speed Buggy
 * Tinker
 * Mark
 * Debbie
 * Neptunes
 * Jabberjaw
 * Biff Starke
 * Shelly LaMarine
 * Bubbles Blowton
 * Clamhead Rogers
 * Captain Caveman
 * Grape Ape, a 30 foot tall giant friendly gorilla with purple fur that resides on Mystery Island with Captain Caveman under Messick Mountain. He later dress himself a giant green t-shirt and hat along the way to the Parthenon to confront Cerberus..
 * Penelope Pitstop
 * Hong Kong Phooey

Villains:
 * Dick Dastardly
 * Muttley
 * Pandora Pitstop
 * Blast-Off Buzzard
 * Rotten Robots (redeemed)
 * Dusty
 * Dastardly Droids, future replacements for the Rottens after the redeem themselves and betrayed Dastardly. They are shown in blueprints aboard the Mean Machine.
 * Cerberus
 * Orthrus, ghostly versions of the mythical two-head dog and serves as Cerberus' smaller avatars

Other Characters:
 * Mr. Rigby/The Ghost
 * Simon Cowell
 * Judy Takamoto
 * Spot
 * Beegle Beagle
 * Atom Ant (Cameo)
 * Dr. Benton C. Quest (Cameo)
 * Johnny Quest (Cameo)
 * Hadji (Cameo)
 * Race Bannon (Cameo)
 * Bandit (Cameo)
 * Mr. Hyde (Cameo)
 * Hideous Hyde Hound (Cameo)
 * Peter Perfect (Cameo)
 * The Gruesome Twosome
 * Tiny and Bella (Cameo)
 * Slag Brothers (Cameo)
 * Sergeant Blast and Private Meekly (Cameo)
 * Ignatius Quinton "I. Q." Ickly (Cameo)
 * Josie and Pussy Cats (Cameo)

Vehicles

 * The Mystery Machine
 * Falcon Fury
 * The Mean Machine
 * Speed Buggy
 * Neptunemobile
 * the Compact Pussycat
 * Phooeymobile