The Journey of Billy and Mandy

is the 2020 animated adventure film based on The Grim Adventures of Billy and Mandy. It was directed by the series creator, Maxwell Atoms who also written it. The film sets in the world where Billy and Mandy are teenagers when they accidentally got transport into the Underworld where they must find a way out before the Boogey Man and Nergel will take over Endsville.

The film sets in the same world as Ed, Edd n Eddy the Movie: The Ed-Touchables and serves as a epilogue of the series. It is the second film of the Cartoon Network's Cinematic World.

Story
The animated film follows two teenagers, a boy named Billy, a slow-witted happy-go-lucky boy who dreams to become a cartoonist, and Mandy—his dark and cynical best friend who decided to become an actress, who accidentally got transported into the Underworld where they meet the Grim Reaper. Now, they must team up with Grim Reaper on a grand adventure to get out of the Underworld before the Boogey Man and Nergel will conquer Endsville.

Plot
The film begins in the Endsvilles hospital, Gladys gave birth to a baby boy named Billy. When Harold asked his newborn son to smile for him. He thinks that he's a genius. Gladys tells him that it was just gas bubble. When Harold looks at Billy again, he thinks that he made his first steps. He held him and called him a genius. At Endsvile park, Harold meets up with Dick, Irwin's father. They put them in a playpen where they see a baby rattle. Irwin crawls to get it, right before he farts crawls before Irwin and held up the rattle. Harold takes Billy to the photo booth and takes a picture. Growing up, Billy walks across the street and meets Mandy. She asked is he some kind of idiot. Billy takes the bottle, puts it in his mouth, then flushes it down by tugging on his nose like a toilet. She takes that as a yes but decided to be friends.

Years later, Billy and Mandy are teenagers and graduated Endsville High School. Billy became a talented cartoonist while Mandy learns to be an actress. One weekend is the birthday of Billy's hamster Mr. Snuggles, who is ten years old and ready to cash in his chips. The Grim Reaper appears to harvest the pet's soul, but is surprised that Billy and Mandy aren't afraid of him.

Mandy tells Grim she won't let him take Mr. Snuggles. She challenges Grim to a game; whoever wins keeps Mr. Snuggles. Grim accepts, certain of his victory, and adds that if they win, he'll be their best friend forever.

Cast and Characters

 * Richard Steven Horvitz as Billy/Harold, Billy is a happy-go-lucky boy who dreams to be a cartoonist and Harold is Billy's father and Gladys' husband.
 * Grey DeLisle as Mandy, Billy's childhood best friends who decide to be an actress.
 * Greg Eagles as Grim Reaper/Sperg
 * Vanessa Marshall as Irwin, Billy's best friend who's madly in love with Mandy. After high school graduation,  Irwin saw him and Mandy kiss which ends their friendship and moved on from Mandy.
 * Rachael MacFarlane as Mindy
 * Martin Jarvis as Nirgel, one of two main antagonists of the film who plans to keep Billy and Mandy in the Underworld forever.
 * Fred Willard as the Boogey Man, one of two main antagonists of the film who plans to steal Grim's powers to conquer Endsville.