When an alien disguised as a cat lands on Earth, Coop Burtonburger's little sister, Millie finds him and brings him home where bedlam ensues.

When 10-year old Coop Burtonburger's spoiled little sister Millie, brings home a mysterious stray cat, Coop's idyllic life is turned upside down. Coop soon discovers Kat is more than just a scrawny, purple, hairless pet; he is also a super-smart, conniving mastermind, and Kat's also an alien with a fanatical hate for Coop himself. Kat instantly declares war on Coop--to the death; the two fight constantly as Coop tries to stop Kat and tell the world about his possible plans, only to find Kat destroying the evidence and putting the blame on Coop every time.—Anonymous

Wjen 10 years old Coop's sister Millie discovered a purple stray cat, Coop becomes suspicious and soonely later discoveres that Kat (the cat) is an intelligent cat-like alien, who hate's Coop. Together with his best friend Dennis, Coop tries to fight and chase Kat away. But nobody else is believing Coop and Dennis, that Kat is more then just a purple, hairless stary cat.