A baby kangaroo, named Hippety Hopper escapes from the crate that he was put in at the Zoo office and runs into the house of Sylvester and his son, Sylvester Junior. They mistakenly think that Hopper is a giant mouse. Sylvester is constantly pummeled over and over again by the Kangaroo. In the end Junior puts a paper bag over his face, in shame. Later it was Sylvester who put a paper bag over his face, in shame, while Junior shared his lollipop with Hippety.