A circus comes to town featuring Gracie the Fighting Kangaroo and her youngster, Hippety Hopper. Hippety slips out of the circus tent and hops into a yard where Sylvester Cat is bragging to his son, Junior, about how good a mouser he used to be. To prove he still has his mettle, Sylvester must fight against the playful Hippety, whom they, as usual, mistake for a giant mouse.