Sylvester checks in to work at a museum with his son, Junior. He is bragging about his mouse-catching prowess, when the baby kangaroo, Hippety Hopper, having escaped from the zoo, turns up in the museum. Sylvester and Junior, as usual, mistake Hippety for a giant mouse and chase him around the exhibits, in an attempt to kill him, resulting to humiliating executions for both cats, with Junior often embarrassed at his father's failures.
When this cartoon aired on ABC's The Bugs Bunny and Tweety Show, the scene of Sylvester getting caught in the lion's head and Sylvester, Jr. blasting him in the rear end with a gun to get him out was cut. Also cut was Sylvester chasing Hippety Hopper around an American Indian display because it showed Sylvester dressed as an Indian and whooping before getting scalped (oddly enough, the American Indian display scene for some reason is not censored on other TV channels such as Nickelodeon, Cartoon Network and Boomerang)
When Nickelodeon aired this short on Looney Tunes on Nickelodeon, only the lion's head part that was also edited on ABC was cut.