- Guardians of the Galaxy
- Nova Corps
- Rhomann Dey (first appearance)
- Nova Prime / Irani Rael (first appearance)
- Captain Marvel / Carol Danvers
- Starforce / Liz Danvers Rogers
- Kree Empire
- Ronan the Accuser
- Ellie Gillan (first appearance)
- Dinah Gillan (first appearance)
- Gamora's biological father (single appearance; flashback only; deceased)
- Gamora's biological mother (single appearance; flashback only; deceased)
- Maxine Joan (cameo)
While sleeping in her bed, Gamora dreams of her past, as a young Chameliel who witnessed a civil war erupting near her village. Not wanting her to take part in the conflict after her cousin Nebula ended up terribly injured, Gamora's parents sent her to a escape pod which set course to Earth for her safety. Her escape pod landed on Earth, where Gamora was adopted and raised by Ellie Gillan and, taking the shape of a human girl, was renamed Zoe. Waking up, Zoe overhears a mysterious female voice saying it is time for her return to her home-planet of Zen-Whoberi, but she is tearfully unsure if she intends to return to her former homeland and leave her adoptive family forever. Just then, a member of the Nova Corps ship crash-lands near her family's farm, with the injured pilot alerting Gamora that Ronan is heading to Zen-Whoberi.
Carol Danvers / Captain Marvel arrives to tend to the pilot's injuries while receiving a call from Denarian Rhomann Dey and Irani Rael / Nova Prime, who inform her that Ronan plans to eradicate Zen-Whoberi's population to harvest its biological resources. They accept hers and the Guardians of the Galaxy's help in dealing with Ronan's fleet. While she goes on to discuss a battle plan with the Nova Corps, Danvers tasks her daughter Liz / Starforce and the Guardians (Nathan Quill / Star-Lord, Gamora, Cougar, Drax the Destroyer, Rocket Raccoon, Groot and Yondu Udonta) to monitor Zen-Whoberi and alert the Nova Corps in case Ronan appears. The Guardians arrive in the planet, encountering Chameliels living like a normal farmer's life. While Rocket and Yondu work on a device which will protect the villages from Ronan's impending invasion, Gamora explores the village to find out where the voice she heard came from. During which, she encounters a shaman who claims to know Gamora ever since she was born. To her sadness, Gamora overhears that after they sent her to Earth, her parents were caught up in the issuing Civil War and killed in the crossfire, while Nebula went missing when the war was over. As Nathan and Liz comfort her, Gamora still hears the female voice calling her name. Following the voice in a deep forest, Gamora eventually encounters the grown up Nebula, who is partially infused with cybernetic implants.
Recognizing Gamora, Nebula tells her that after the Civil War was over, the doctors tried to revive her by replacing her most damaged body parts with cybernetic components of nanotechnology, turning her into a cyborg in the progress. Horrified with the drastic changes however, Nebula exiled herself and never returned to the village. The two cousins comfort each other as Gamora vows that they find a way together and encourages her to meet her fellow Guardians, with whom she is quick to warm with. They also review the capabilities of Nebula's implants, which have granted her the ability to manipulate technology and magnetic fields. Nebula uses this to turn the unbreakable chains in her arms into a pair of nanotech bracelets which can summon any weapon she thinks of. While some of his Sakaarian crew attacks one of the Nova Corps' warships, Ronan arrives on Zen-Whoberi, where he orders to prepare his doomsday weapon. Rocket and Yondu spot Ronan and his crew and alert the rest of the Guardians and Captain Marvel. The Guardians battle Ronan and his crew while Captain Marvel drags the doomsday weapon away from the planet. Star-Lord, Gamora and Nebula directly attack Ronan, causing one of his teleportation devices to teleport them to Earth, near the Gillan Farm.
The fight continues as Ronan voices intentions of killing Gamora's loved ones (including her friends and adopted family) as punishment for hers and Nebula's interference. On her cousin's defense, Nebula replies that Ronan is the one who should face punishment for invading other planets and threatening their people, as she and Gamora were just trying to defend their former home. The fight continues, ending with Gamora (discovering that her sword Twilight Talon can absorb and redirect energy) defeating Ronan, scarring his left eye and destroying his Universal Warhammer, which is powered by a prototype duplicate of the Power Infinity Stone. After Groot arrives and infuses Ronan with a brain virus which will render him amnesic, Nebula uses one of the Kree teleporters to send Ronan to another part of space, where he is left helplessly frozen. As the Chameliel voice gratitude for the Guardians and the Nova Corps for saving their planet from the Kree threat, Gamora is expressing herself hesitant in leaving Zen-Whoberi behind, but Nebula eventually decides to stay with her and the Guardians on Earth as she states to have no one else in the family but Gamora, and wherever her cousin is, she is home. As Nebula visits Pegasus Z with Groot, Gamora embraces her adopted family and Nathan, feeling confident that she is indeed home.
- Scott Menville as Star-Lord / Nathan Quill
- Laura Bailey as Gamora / Zoe Gillan
- Dove Cameron as Starforce / Liz Danvers Rogers
- Troy Baker as Rocket Raccoon / Sebastian Allan, Gamora's biological father
- Travis Willingham as Groot
- Erica Lindbeck as Nebula
- William Salyers as Yondu Udonta
- Jennifer Hale as Captain Marvel / Carol Danvers
- Tara Strong as Dinah Gillan
- Gwendoline Yeo as Ellie Gillan, Gamora's biological mother
- Susanne Blakeslee as Nova Prime / Irani Rael, Chameliel village shaman
- Benjamin Diskin as Denarian Rhomann Dey, Unnamed Nova Corps Pilot
- Jonathan Adams as Ronan the Accuser
- The episode is entitled after a song by Jordin Sparks for Disneynature's nature documentary African Cats.
- "When The Stars Go Blue" by The Corrs featuring Bono