The film opens with Grandma Gigi [Gloria Estefan] crafting a sprawling dollhouse filled with tiny cat figurines, a tender piece of whimsy that she gifts to her granddaughter Gabby [Laila Lockhart Kraner]. Along with the dollhouse, she gives Gabby a pair of magical cat ears and a plush doll, Pandy Paws, that shrink her down and open a doorway into the dolls’ world. In the present, Gabby is getting ready to travel to Cat Francisco with the dollhouse and the Gabby Cats — Pandy, CatRat [Donovan Patton], Cakey [Juliet Donenfeld], Baby Box [Maggie Lowe], DJ Catnip [Eduardo Franco], Kitty Fairy [Tara Strong], MerCat (a creature of the water), Pillow Cat [Sainty Nelsen], and Carlita [Carla Tassara]. When Gabby shrinks, she joins her friends inside the dollhouse’s vibrant realm, sometimes called Gabby’s Dollhouse World, and the group sets off on adventures together.
The journey begins with Grandma Gigi arriving to accompany Gabby and the Gabby Cats on a road trip toward Cat Francisco. They pause at several stops, building anticipation and wonder, until a hiccup occurs: CatRat accidentally loosens the latch that keeps the dollhouse secure, and it rolls away into the streets. Gabby chases after it as the Gabby Cats frantically try to steer the magical structure away from danger. The runaway dollhouse wheels past a street cart, where an eccentric cat lady named Vera [Kristen Wiig] spots it. Vera, famous for glittery kitty litter and always accompanied by her cat Marlene, approaches, but a Kitty Ranger denies her the chance to play and instead pays the cart owner to take the dollhouse away.
Vera brings the dollhouse home and forces a startling reorganization: the Gabby Cats are scattered to different corners — MerCat in an aquarium, Kitty Fairy outside, and the rest tucked inside. CatRat ends up in a drawer, and his paw touch triggers life in other cat-themed objects, including an old doll named Chumsley. Gabby, guided by Pandy, gets separated from the others in Cat Francisco and sets out to recover them, meeting Chumsley and four animated cat pencil toppers who come to life and offer clues about Vera’s plans. Chumsley explains Vera’s mindset—she doesn’t intend to play with any of the cats—and Gabby resolves to rescue her friends.
Gabby and Pandy venture into MerCat’s aquatic realm, where they become mermaids and discover that much of the underwater world has embraced MerCat as its own. The see-through bubbles carry them to a surface that reveals Baby Box waving a flag from inside Vera’s purse, but Vera soon opens a doorway that blasts Gabby, Pandy, and MerCat back into the garden. They are greeted by a cadre of kitty gnomes who usher them to their queen, Kitty Fairy, and the gnomes deck them out in new outfits before bringing the group to Kitty Fairy. Kitty Fairy happily reunites with her friends, and Gabby ingeniously leads a playful Hide and Seek distraction that buys them precious time to plan an escape. The Kitty Ranger and friends arrive to challenge Vera, nudging her toward a more cooperative path and helping the group assemble a way back to the dollhouse.
Back inside Vera’s home, the team re-enters the dollhouse—but chaos erupts as Chumsley uses the magic to wreak havoc. When Gabby tries to reason with him, he reveals a backstory: he and Vera used to be best friends when she was a child, but as she grew up, she stopped playing and left him behind. This heartbreak fuels Chumsley’s plan to seize control of the dollhouse by flushing Gabby and her friends out with a shower of bubbles. Pandy and DJ Catnip enlist Carlita to drive to Gigi’s house to recruit help, and Grandma Gigi herself shrinks to join the fray, bringing a new ally into the mix. With Gigi aboard, Gabby is able to confront Chumsley, who seizes Gabby’s magical ears and taunts her with the fear of growing up and losing the ability to play.
In a heartfelt moment, Baby Box offers encouragement to Gabby, sharing her own growth and resilience, and helps her reclaim the magical ears from Chumsley. Gigi arrives just in time, lending Gabby the ears so she can speak directly with Vera. Vera, initially unsettled by the idea, agrees to join them in shrinking once again and helps them slip back into the dollhouse through a new portal they open together.
The trio—Gabby, Vera, and Chumsley—step through a portal that opens when Chumsley’s cake-baking overload destabilizes the dollhouse’s magic. They traverse a confectionery land filled with sweets, aided by the friendly monster Cookie Bobby who helps them reach a cookie wafer bridge Chumsley is crossing. Vera’s initial distrust softens, and she and Chumsley reconcile after a dramatic moment: Chumsley saves Vera from a misstep as the bridge collapses. The magic of the dollhouse begins to fade, but Gabby uses her own magic to create star-shaped platforms that allow Chumsley to cross safely, and the group returns to the dollhouse on solid footing.
With the magic restored, Vera and Chumsley form a renewed friendship, and Vera expresses that Gabby is on the path to becoming a wonderful grown-up. The Gabby Cats and their companion travelers rise above Cat Francisco on a bright ascent, guided by the joy of play and companionship. Back home, Gabby helps Grandma Gigi with a new project: a dog-themed dollhouse for Gabby’s little sister, closing the adventure with a hopeful look toward continued imaginative play and family bonds.
