Tommy has trouble adjusting to the mundane life at his new firehouse and takes out his frustrations on street vendors hawking Sept. 11 memorabilia. Later, he has a confrontation with Johnny. Meanwhile, Sean plays a crude joke on Laura that backfires on him.

Tommy finds out his wife and kids are living in Ohio, so he joins his firehouse's barbershop quartet, who happen to be traveling there for a singing competition. Elsewhere, Mike flies off the handle after Theresa breaks up with him; and Lou tries to get Tommy transferred back to 62 Truck.

Chief Perrolli agrees to let Tommy come back to the station on one condition: The crew must vote unanimously to trade Sully for Tommy. Elsewhere, things heat up between Franco and Laura; Theresa files a restraining order against Mike; and Tommy's dad remarries.

Lou faces heat from headquarters for using a derogatory term to insult Laura. Meanwhile, the guys try to convince her that name-calling is part of the job. Meanwhile, Tommy injures his hand when he has another dispute with a cop over a parking ticket; and Johnny Sr. wants to become a plus-size model after he learns that Uncle Teddy is making a fortune.

With Colleen's help, Tommy gets another chance to find the kids and bring them back to New York. Also, Jerry needs his son's assistance when his wife's condition gets worse; and a priest tells Tommy and Johnny that he is part of their family. Peter: Neal Jones.

Tommy finds out about Sheila's miscarriage and reacts badly. He later gets a visit from Jimmy, who orders Tommy to get her pregnant again. Also, Sean learns his new girlfriend has a suspicious past; Jerry has trouble communicating with his son; and Tommy gets kicked out of his apartment.

Franco goes to support-group meetings to get help for his addiction to painkillers; Lou runs into Sondra and lies about his love life; Jerry meets his son's life partner (David Alan Basche); Tommy and Johnny meet their half sister (Noelle Beck); and Mickey has an uneasy feeling about Father Murphy (Scott Winters).

Jerry forces the crew to attend a birthday party that his son is throwing for his boyfriend. Meanwhile, Tommy makes a move on Mariel (Noelle Beck) after she tells him she might not be his half sister after all; Franco asks Laura to move in with him; Sheila tries to make Tommy jealous by showing off her new girlfriend.

Tommy discovers that Janet is taking antidepressants, and he decides to take some for himself. Elsewhere, Sean tries to make things right between Franco and Laura, but he only makes things worse; and the crew questions Mike's sexual orientation after a gay guy stops by the station looking for him.