Early in the morning, the milkman leaves a fresh bottle of milk at the doorstep. The greedy Tom, seizing the opportunity while his owner isn't looking, secretly takes the milk for himself. Just as he is about to enjoy the milk in his bowl, he discovers that the little mouse Jerry has unceremoniously come to the dish and started feasting. The stingy Tom naturally won't allow Jerry to share his treat, and he repeatedly tries to drive away this pesky little creature. However, Jerry seems determined to get his share of the milk. Furious, Tom hides in the laboratory and mixes various strong acids to create a highly toxic milk, which he then places at the entrance of Jerry's hole. 　　Unaware of the trap, Jerry drinks the milk in big gulps and ends up collapsing in pain at the entrance of his hole. Before Tom can even rejoice, he discovers that Jerry has instantly transformed into a monstrous creature with enormous size and overwhelming strength. This time, the foolish Tom has only himself to blame...