Ten-year-old Coop Burtonburger lives an ordinary suburban life in Retroville until his younger sister, Millie, brings home a strange, hairless, stray cat she names Mr. Kat. Unlike normal felines, Kat possesses hyper-intelligence, advanced technological prowess, and a secret agenda to conquer Earth. Coop immediately discovers Kat’s true nature, sparking a fierce, paranoid rivalry. Coop’s primary motivation is self-preservation and protecting the planet, while Kat seeks to eliminate the meddling boy to successfully complete his alien mission.Every episode escalates their comedic cold war. Coop attempts to expose Kat using video cameras, elaborate traps, and makeshift gadgets, but Kat always outsmarts him. Kat routinely sabotages Coop’s life, framing him for destruction and ruining his reputation with his father, Burt, and his best friend, Dennis. Coop’s motivation shifts from mere survival to desperate vindication, as he constantly tries to prove to an oblivious world that his household pet is a malicious
extraterrestrial overlord.Complicating Coop’s crusade are various supporting obstacles. Millie fiercely adores Kat, treating him like royalty and violently defending him whenever Coop strikes back, ensuring Coop always bears the brunt of the domestic fallout. Additionally, Fiona, Coop’s oblivious crush, adores Kat, forcing Coop to carefully plan his attacks to avoid looking like a monster in her eyes. Meanwhile, Old Lady Munson, the grumpy neighbor, serves as an unpredictable chaotic element who frequently catches Coop in the crossfire of his war with the alien.As the series progresses, the stakes continuously rise. Kat’s overarching motivation centers on contacting his home planet and repairing his damaged spaceship using stolen Earth resources. Coop continuously thwarts these grand schemes, occasionally forming uneasy, temporary truces with Kat when mutual threats emerge, such as other alien species or catastrophic natural events. Despite outsmarting most adults, Kat consistently underestimates Coop’s relentless tenacity.In the ultimate dramatic showdown, Kat finally manages to summon a massive alien armada to invade Retroville, driving the series toward its high-stakes climax. Coop refuses to surrender, rallying his friends and utilizing salvaged alien tech to lead a counter-offensive. Through sheer bravery and quick thinking, Coop successfully disrupts the invasion fleet, forcing Kat’s mothership into retreat. Although Kat remains stranded on Earth, unable to conquer the planet due to Coop's constant vigilance, the eternal stalemate between the boy and the alien continues. They remain locked in an
endless cycle of domestic warfare, forever bound by their mutual hatred and grudging respect.