A pregnant woman named Gretchen gets stuck in an elevator with Homer. With the help of Homer, she gives birth to baby boy and names the child Homer Jr. Homer makes bonds with the child. And he also takes an immediate liking to the child, and the child seems interested in Homer a lot.
The story begins with Maggie trying to choose a new pacifier because Santa's Little Helper took her old one. After refusing each pacifier, Marge takes the old one back from Santa's Little Helper and washes it, making Maggie satisfied(but not Santa's Little Helper). Lisa comes in the kitchen and starts relaying facts about "American Football" (as she puts it), since Milhouse asked her to an Atom's game. Homer lying to Marge, pretends he has to work late "again." However, he is really playing poker every night with Lenny, Carl, Moe, and Barney, at Carl's apartment. Later that night, everyone folds their cards, Lenny states that Homer is doing particularly well this evening. Homer lying again claims that it is just a stroke of luck; however he is really playing so well because he can see everyone's cards through the reflection of Lenny's sunglasses. While consulting his conscience about cheating his friends, lying to his wife, and avoiding the kids, Homer imagines what Jesus would say. Jesus, in his thought while playing poker says, "You gotta pay to find out, you're looking for a tell, well I don't have one my friend." His halo then spins in a circle, revealing his tell. Jesus then tries to hide it by saying, "What? What are you looking at?"
Homer plans to leave because he doesn't want to take anymore of the guys' money. However on his way out, he takes two beers, a sandwich, and a candle. Homer leaves Carl's apartment and goes to the elevator, and just as it is about to close a woman yells for him to hold the doors. The woman, who we find out is pregnant, is looking at her watch and saying two minutes apart, referring to her contractions. Homer stupidly believes she is timing the elevators. The woman then begins to panic because she is about go into labor. Suddenly, the elevator light goes out and Homer lights the candle he stole from Carl's apartment. She lays down on the floor with her head in Homer's lap, while Homer tries to calm her down by talking about the movie "Alien." The woman tells Homer she's glad she isn't alone and tells him that she hasn't seen her boyfriend in a month. Homer tries to comfort her, lying once again by saying, "he was just here." Even though she knows he isn't telling the truth she still thanks Homer for trying to make her feel better. When the woman cries out that the baby is coming, Homer tries to remember back when Marge was pregnant in lamaze class. The teacher of the class in Homer's memory was demonstrating a comfortable position for larger pregnant women on Homer. Homer, while in this position, believed that he was having a baby and yelped that he hasn't even picked out a name yet. As the baby is born in the elevator, Homer puts his coat between her legs to wrap the baby. The baby turns out to be a boy or a "dude" as Homer puts it. After the woman says it was nice to share this with someone who cared, Homer points to a man in the corner of the elevator and says "yeah that guy didn't even look over once". The guy in the corner then replied by saying, "lobby please."
The next day Milhouse and Lisa are at the Atoms game, when the Atomettes (the team's cheerleaders) come on to the field. One of the ladies picks a Jr. Atomette out of the crowd, which happens to be Lisa. With the help of the cheerleaders, Lisa performs with the group, on the field. Milhouse proudly states, "I'm dating a cheerleader!" to which Lisa quickly responds by saying, "No you're not!". After the game Lisa waits to thank the cheerleaders, when the Rich Texan interrupts because he has to pay them. Lisa is outraged when she learns that the girls only get paid $50 a game, which just covers their parking. The cheerleaders are afraid to fight back because they don't want to end up wearing the mascot costume.
Back at Carl's apartment Homer leaves and runs into Gretchen, the woman from the elevator. She returns the jacket Homer used when he delivered the baby, and asks him if he wants to hold Homer Jr. (the baby). The next night, Homer returns with old baby things that he didn't need anymore. Gretchen asks Homer if he could babysit Homer Jr. because she hasn't been away from the baby at all. While Gretchen is gone Homer and Homer Jr. play The Simpsons: Tapped Out on Homer's phone and the game charges $300 to Homer's credit card. Next, they play peek-a-boo and Homer loses "Hoju" while his eyes are closed. He then runs out the window and down the fire escape looking for him. However, the baby is just hiding under a blanket back in the apartment. Homer also, combs Hoju's hair and puts two M's behind his ears, so the baby would look like him. As Maggie was sitting on Homer's lap, Homer imagined she was Homer Jr, while Maggie imagined Homer was Ned. Homer accidentally runs into Marge at the grocery store, while he is buying baby supplies for Homer Jr. Marge believes Homer is shopping for Maggie, so once again he lies.
Meanwhile at the Atom's Stadium, Lisa goes to visit the cheerleaders. The Rich Texan refuses to pay them anymore money, so Lisa convinces them to go on strike. Lisa gathers the Atomettes in Bart's treehouse, causing a crowd of men to circle around them. With Homer missing, Marge goes to Carl's apartment because she suspects he's playing poker. When she finds he isn't there, she walks down the hall toward Gretchen's apartment and over hears Homer saying, "Shake it!" Marge opens the door and finds Homer and Hoju playing with a rattle. Gretchen and Homer explain the story to Marge, and she says it's probably for the best if he stops seeing the baby. However, she changes her mind when she sees how close he is to Hoju. Outside of the Atom's Stadium, Lisa and the cheerleaders are protesting; therefore the team is forced to get a new group of cheerleaders consisting of Patty, Selma, Mrs. Muntz, and Crazy Cat Lady. Finally, the Rich Texan gives in and gives the girls a raise.
Later that day, Homer chooses to take the kids and Homer Jr. to the zoo. At the zoo Homer Jr. and Maggie are sitting in a stroller together. When Homer Jr. takes a bite of Maggie's ice cream, she slaps him. Homer tries to make the kids feel better by trying to "out monkeying the monkeys," it goes fine until the monkeys grab Homer through the bars. Maggie then pushes Hoju out of the stroller and he pushes her, causing the stroller to roll backwards. Maggie barely saves herself by using a dino wand on the wheel. A little further and she would have been in the prairie dog village. Afterward, Marge forbids Homer to see the baby ever again. Homer then walks Homer Jr. home, only to see that Chase (the baby's biological father) has returned from the war. When Homer comes home, Maggie gives him her doll to cheer him up and he picks her up and hugs her. Maggie then imagines Ned with a baby bottle, but it quickly turns to Homer with a beer bottle.