Set in the fictional town of Drabville, a quirky place where humans and animals share space in all shapes and sizes, a spoiled orange tabby named Marnie Alexandra Neldel is pampered by her nurse mistress Rosalinde Sunshine Addison Rae. Marnie spends her days indulging in pastries, lounging in front of the TV, and dreaming of adventures she’s never allowed to have outside. Despite her cozy life, a spark of curiosity burns in her, a longing to become a spy and uncover secrets beyond the hospital walls of her world.
Paul Obada Adnan arrives in Drabville under the guise of a wounded visitor, but his real purpose is far more sinister. He’s a thief who has stolen from cities around the globe—Paris, Tokyo, London, Buenos Aires, and New York City—and he’s in town with two accomplices to lift paintings and other valuables from Drabville’s quiet streets. Marnie, ever observant, notices Paul’s suspicious moves and begins to spy on him, snapping a picture that could expose his plan. When she refuses to hand over the photo, Paul tricks the cat, getting her removed from Rosalinde’s sight and sending her away against her mistress’s wishes. A misstep soon follows when the box containing Marnie tumbles from a delivery truck, leaving the feline heroine stranded in the middle of a bustling road.
On the road to an unexpected fate, Marnie encounters Eggbert the rooster Sylvain Urban, who is desperately trying to outfly a flock of hens that want to turn him into soup for being “irresponsible.” She also meets Elvis the dog Axel Prahl, a creature who has suffered abuse at the hands of humans, including a pumpkin farmer who once treated him as a coward. Marnie explains her mission to these unlikely allies, and together they make a bold escape on Elvis’s tractor. Their journey continues when they meet Anton the donkey [Erik Borner] who is pretending to be a zebra to join a traveling circus. The foursome—Marnie, Eggbert, Elvis, and Anton—flee in a van owned by Paul’s men and spend the night in an old, deserted barn as Rosalinde grieves for her missing cat and the police photograph a group that looks suspiciously like the four escapees.
The next day, Marnie uncovers the stolen paintings and suggests turning them in to the police as evidence. But the authorities mistake the group of animals for the actual burglars and chase them, unaware that the real thieves are still at large. The quartet hides in a hayfield, and a rainstorm begins to wash away Anton’s painted zebra stripes, forcing him to reveal his true identity. With the mystery deepening, Marnie tracks down the artist who created the paintings, then uses an online search to identify the thief’s next target. She convinces her friends to head back toward Drabville to uncover the truth behind the heist and the artist behind the forgeries.
Their investigation leads them to Eggbert’s farm, where the truth about Paul emerges: he is the thief. Marnie captures a photo of him, which Paul then tries to use as leverage, threatening to harm Eggbert if the photo doesn’t fetch him the goods. Eggbert is taken hostage, and Elvis grows frustrated with Marnie’s choices, blaming her for the danger. The situation worsens when Marnie ends up in solitary confinement at an animal shelter, a punishment that devastates Rosalinde.
Hope arrives in the form of Eggbert, Elvis, and Anton, who return to rescue Marnie. United again, the four heroes race back toward Drabville, determined to stop Paul. They distract him while they summon the police via the TV, ultimately trapping Paul in Rosalinde’s basement. Paul escapes once more, fleeing with the paintings in a flying wheelchair, and Rosalinde is taken along for the ride.
The chase continues as the makeshift squad follows in an aerial pursuit to save Rosalinde, culminating in a dramatic crash that lands them inside a circus. In this surprising twist, the circus animals are revealed to be innocent, and Paul is finally captured along with his accomplices. Rosalinde apologizes to Marnie for the way she mistreated the cat, acknowledging the bond that formed between the four unlikely allies.
With the stolen paintings returned to their rightful owners, the four heroes are rewarded for their bravery. Yet the reward proves secondary to the companionship they’ve discovered. Rather than part ways, Eggbert, Elvis, Marnie, and Anton decide to stay together, choosing to continue their adventures and bring more outlaws to justice wherever their open road leads. They set off in a custom-built motor vehicle, ready to face whatever challenges lie ahead as a united team.
