Things are not going well for Tommy Gavin (Denis Leary). His wife Janet (Andrea Roth) has taken the kids, sold the house and left him. His girlfriend, Sheila (Callie Thorne), is pregnant. He is bored out of his mind at the Staten Island firehouse he has recently been assigned to. And his drinking is spiraling out of control. Tommy hits rock bottom and calls on his former crew mates from 62 Truck to try and help him get his life back on track.
When Tommy discovers where Janet has taken the kids, the only way he can get time off to find them is by joining his new firehouse's competitive Barbershop Quartet. Lou and Chief Reilly conspire to get Tommy back into the old firehouse, but the rest of the crew is getting attached to Tommy's replacement, Sully, who's a gourmet cook with great people skills. Mike has trouble controlling his emotions when his girlfriend Theresa breaks up with him.
Chief Reilly and Lou have trouble convincing the crew to take Tommy back into the firehouse, until a huge warehouse fire reveals a secret about Tommy's replacement, Sully. Tommy's dad returns from his trip around the world with a new wife and a brand new lifestyle. Franco and Laura take their friendship to a new level while Mike finds himself stalking his ex-girlfriend. Sheila can't bring herself to be honest with Tommy about the baby.
Tommy looks to his cousin Mickey, now an ex-priest, for help in understanding the bizarre visions he's been having since he quit drinking. When Lou allows a disagreement with Laura to escalate, the crew tries to help Laura understand the essence of male camaraderie. Tommy is put in harm's way during a fire when a miscommunication happens between Chief Reilly and Mike The Probie. Tommy's Dad is shocked when Teddy turns up in the last place he would ever expect.
When a priest delivers some startling news, Tommy wonders if his Dad has been living a double life. Chief Jerry discovers just how far his wife's mind has slipped, and he is forced to ask for help from his estranged, gay son. When Laura files a complaint against Lou, the whole crew is ordered to undergo sensitivity training. Now that Colleen is home, Tommy comes up with a plan to get the rest of his kids back; meanwhile, Tommy starts to suspect that Sheila is hiding something from him.
Lou regrets participating in the FDNY bone marrow donation program when he meets the miserable person whose life he saved. Sean becomes suspicious of his new girlfriend when he discovers her habit of dating firemen. Franco's worsening painkiller addiction puts his daughter at risk. Tommy tries to learn the truth about Sheila's pregnancy, while executing a new plan to take his kids back.
Tommy finds himself keeping vigil at the bedside of a young boy who was critically wounded in a fire. Chief Reilly learns a little more than he can handle about his gay son's relationship. Lou comes up with a plan to attract the attention of an old girlfriend.
Chief Reilly doesn't know what he's in for when he invites the crew to attend a birthday party for his son's boyfriend. Just as Franco and Laura's relationship is becoming serious, Laura learns a devastating secret. Tommy finds himself being tempted by a woman who's off-limits, while suddenly being forced to make a decision about his family's future.
Tommy finds a less-than-perfect way to rekindle his relationship with Janet. Franco asks for the crew's help in winning Laura back. Tommy's ideas about faith are challenged when an accident on the job nearly kills him.
Tommy, Johnny, and Mickey's investigation into Father Murphey's private life leads to tragedy. Laura starts to believe that one of her crew members is secretly harboring romantic feelings for her. Tommy unwittingly becomes involved in a domestic dispute between Sheila and her new girlfriend.
Sheila begs Tommy to talk to her teenage son out of his decision to become a fireman. Franco's attempt to make Laura jealous backfires when his hot blind date turns out to have a big physical flaw. Tommy goes out of the way to prove to his hockey teammates that he hasn't gone soft.