A mouse about to commit suicide by jumping off a pier, when he was saved by baby kangaroo, Hippety Hopper. In exchange for the mouse releasing him from his shipping crate, Hippety agrees to help the mouse humble his tormentor, Sylvester Cat, by making Sylvester think that vitamins have enlarged the mouse to Hippety Hopper's size, and when Sylvester fights the "giant mouse", he loses in the usual embarrassing way- this time, in front of a chiding bulldog. The duo also embarrass the bulldog after threatening to pin its ears back, The bulldog and Sylvester then start ballet as this concludes.