While playing poker one night with Moe, Barney, Lenny and Carl, Homer has a run of good luck and decides to leave the game with his winnings. A pregnant woman, Gretchen, enters the elevator with him to ride down to street level, but it gets stuck between floors and she goes into labor. Based on what he can recall of the childbirth classes he took with Marge, Homer manages to deliver the baby himself, a healthy son. Later, after another poker night, Homer comes across Gretchen again and learns that she named her child after him. He begins to spend time with her, bringing baby items that he and Marge never used for their children, instead of going to the poker game.
Marge, thinking that Homer has sneaked out of work in favor of the game, discovers that he is in Gretchen's apartment and thinks at first that he is being unfaithful to her. However, she eventually learns the whole truth, and Homer takes his children and Homer Jr. to the zoo. In a fit of anger, Homer Jr. pushes Maggie's stroller toward a prairie dog exhibit, but she manages to stop herself before she can roll into it. Marge forbids Homer to see Gretchen ever again, and he takes Homer Jr. back to the apartment, where he returns the baby to Gretchen and her husband - recently returned from a military deployment overseas. A dejected Homer returns home, where Maggie quickly forgives him for not paying attention to her, and Homer Jr. surprises his father with his ability (learned from Homer) to open and pour a beer.
Meanwhile, Lisa taunts Bart with the fact that Milhouse has invited her to a Springfield Atoms football game. During the halftime show, the team's cheerleaders, the Atomettes, invite Lisa onto the field to take part in one of their routines. Lisa enjoys herself, but after the game, she discovers that the Atomettes are poorly paid. She persuades them to go on strike in order to force the team owner to grant them a better contract; the strategy succeeds, but in the meantime they begin to endorse many bizarre products and services, to Lisa's surprise and dismay. As the credits begin, several Atomette-sponsored items are shown.