Once upon a time, near the ruins of an old castle, there lived the King of Cats. He was famous for his violent temper and now he is lashing out at his three gunmen, who had been ordered to bring back Pero, but had returned empty-handed. Pero, a former subject of the angry King, had lived in Cat Country once but he had dared to save a mouse from death. Now, as everyone knows, the mouse is the mortal enemy of all cats, so the King orders his three gunmen to go to the ends of the earth, if necessary, to find Pero. Pero is a happy-go-lucky sort of feline and very hip for a cat.