On the planet Dorkon, Professor Wally, Neil Ross, unveils the Moscram ray gun, a device powered by the Klopman crystal that can scramble inanimate objects and living beings into new creatures under the user’s control. Emperor Jon, Wally Wingert, is more interested in finding a wife to continue the royal line than in mastering the science, and soon a warship led by Vetvix, Vanessa Marshall, lands outside the palace. Jon instantly falls in love with her and asks if he can marry her, a union Vetvix quietly senses could help her seize the Moscram for herself. She agrees, to the cunning of a plan that would turn the Emperor’s desire into a gateway for domination.
Professor Wally summons the Pet Force—Garzooka, Odious, Abnermal, and Starlena—to stop Vetvix, but the villainous queen zombifies all of them except Garzooka. Garzooka, Frank Welker, seizes the Klopman and escapes with the Professor, who begins to realize the scale of Vetvix’s ambitions. As their escape unfolds, the Professor discovers that there are DNA matches elsewhere in the world, and he uses this discovery to craft serums that can transform the Pet Force into their heroic forms. Garzooka is joined by the others in his mission: Starlena, Audrey Wasilewski, becomes the fearless Arlene’s heroic alter-ego; Odious, Gregg Berger, suits up as Odie, and Abnermal, Jason Marsden, takes on Nermal’s brave persona. The four of them—Garzooka, Odious, Abnermal, and Starlena—take off for Comic World, leaving Professor Wally and Vetvix behind to contend with the escalating crisis.
Within a meta twist, the story reveals itself to be unfolding inside a comic book that Nermal has been reading. Garfield’s friends—Arlene, Odie, and Nermal—go to the Comic Studios without him, and Nermal fetches a new Pet Force issue that seems to foreshadow their fate. Garzooka bursts out of the pages, and soon he heads toward Jon’s house with a message for Garfield: the key to stopping Vetvix may lie in the serums and the Klopman. When Garzooka arrives, he gives Garfield the Serums and the Klopman, initiating a sequence in which Garfield’s friends begin their transformations into Pet Force versions. The group moves toward the studio where the rest of the gang are, but Vetvix is hot on their trail, capturing Garfield by mistake and seizing the Klopman. Garfield escapes, but the clash with Vetvix intensifies the stakes.
Back at the Comic Studios, Vetvix unleashes her Moscram-powered zombification on most of Toon World’s inhabitants. Nermal, Odie, Arlene, Jon, and Garzooka escape and join Garfield, while the serums finally transform Arlene, Nermal, and Odie into their Pet Force forms. Garzooka and his new team pursue Vetvix into the tower, where the head technician Eli, Greg Eagles, fights to keep the power in check. Jon becomes a target of the zombification, which spreads across Toon World, and the Pet Force must regroup to prevent complete domination.
With Garfield trapped and the town’s defenders overwhelmed, Eli uses the Moscram to save Garfield and assist in restoring the others, while Emperor Jon and Professor Wally break free and retake control of the ship. They fly into the air, forcing Vetvix to lose her grip on power as she plummets from the vessel. Garfield re-enters the ship and seizes the Moscram again, dezombifying the Pet Force and destroying the monstrous threat looming over the town. In the climactic moment, Garfield uses the Moscram to fuse Vetvix with a happiness invention, turning her into an ally rather than an enemy. Eli then reverses the zombification on everyone else, restoring Toon World to its former state and removing the looming threat to the world.
With the danger receding, Vetvix recognizes the error of her ambition and apologizes to the Emperor, accepting his real marriage proposal this time. The Pet Force returns to their world, and the Toon World residents begin the long process of rebuilding their civilization. Garfield and Arlene share a quiet, hopeful moment, choosing to stop missing out on life and to seek more adventures together among the stars, where a dance awaits them.
As the credits roll, the wedding of Emperor Jon and Vetvix is celebrated by the Pet Force in attendance, with a few surprises along the way. Betty, Jennifer Darling, stows away on the ship to follow Garzooka, much to her husband’s astonishment, while Wally finds himself in need of a new assistant. Nermal, eager for the chance to contribute, steps into that role, hinting at a new chapter for Toon World’s team. In the final, hopeful note, Professor Wally vows to safeguard the Moscram by pursuing a reverse-engineered solution, determined to prevent further chaos and to protect the friendships that helped save their world. The stars beckon Garfield and Arlene toward new adventures, a reminder that life is brighter when they reach out and take part in it together.
