Alvin tries to play baseball with his team and care for a bratty baby, Billy Brown, at the same time. While Alvin is playing, Billy keeps bugging Alvin to let him play ball, but Alvin won't let him since he is too young. When his team is losing (with the bases loaded), Alvin has the infant play against the rival team's lead player Roger. The little guy, given the nickname "slugger", hits a home run and wins for Alvin's team.