The local bully, Lumpy Rutherford, has been picking on Beaver and Wally. Thanks to a story Ward tells them, the boys decide to play a joke on Lumpy. However, their ploy catches the wrong person. Lumpy's father and Ward's co-worker Fred Rutherford, is caught in the trap.

After Ward's bragging about Wally and Beaver being responsible, Herb and Janet Wilson assume that it would be all right to leave their 4-year old daughter in Wally and Beaver's care while they go out to a party with Ward and June. Trouble begins when the youngster locks herself in the bathroom.