Kelly and Shay discuss each of their living arrangements over lunch. Shay asks Kelly about Renee's due date and says that the first week of November is the latest it should be. Kelly gets upset that she implies that the baby isn't his.
On their way to a fire, Shay tells Gabriela that she thinks the baby may not be Kelly's. Joe Cruz asks Matthew Casey if it is good to be back. Matthew says he feels better than good. At the fire, Chief Boden says that someone is inside. A few firefighters begin to head in but the chief stops them when he smells something. There is an explosion from inside the house. The firefighters break car windows to attach the hose to a fire hydrant. Two firefighters go inside to look for the woman inside. They can't find her and continue to look through the house. On the way downstairs, the stairs collapse and Kelly is trapped in the basement. The chief helps to pull him out using a hose and he escapes the burning basement.
Outside the house Kelly assures everyone that he is okay. Peter Mills tells the chief that there is no one inside. Boden looks at the house and leaves, angry. Kelly looks at the side of the house and sees the number 1751 on the house. He points out that it is also his badge number.
Back at the station, Mouch introduces the boys to his girlfriend Mari. Matthew sees Kelly with a blank look on his face. He suggests that his badge number was just a gang, tagging numbers on buildings and there is no connection to him. Boden is at headquarters with the other chiefs. Gail McLeod has been hired to reduce fire department spending. She explains that "the wizard" will be used to make spending decisions. Boden says that it may save money but it will take away the important decisions that the chiefs make. He asks if she knows what it is like to be the one fighting a fire. Gail has never experienced anything like that but she does have to make difficult decisions. Today she had to shut down a firehouse and there are still two more that need to be closed. Boden is at the meeting because his firehouse is on the short list.
Gabriela enters Matthew's office and says Herman and Otis are driving her crazy. She asks Matthew if he wants to go out tomorrow night and he says yes. She says it's great to have him back.
Boden informs all of the firefighters that they will all have to tighten up on expenses and join a wellness program.
At the hospital, Gabriela and Shay discuss Matthew when a car drives by. A man is pushed out of it and the car speeds away. The man has multiple gunshot wounds and is bleeding profusely. Police stop the car but the men inside make a run for it. The gunshot victim is dying and Gabriela administers CPR but it is too late.
Boden calls Peter into his office and asks how he is doing. Boden tells Peter that a firefighter from another department will be joining the rescue squad. Peter says it sounds good and asks if there is anything else.
Kelly calls Renee and leaves a voicemail asking her to call back. Mouch says that transfers from a closed house is never a good thing. The men complain about signs telling them to vote for Greg Sullivan as Union President. He is running unopposed in the race.
Matthew arrives home and Heather tells him that it will be a year on Thursday. She's going out with some friends but he happens to be working and can't go. Heather's son is upset when he sees Matthew in a fire department shirt.
Gabriela and Herrmann recruit Joe Cruz to go to the newly opened bar, Game Day, as a secret shopper.
At the gym Antonio gives some advice to Peter about boxing. Antonio mentions that he saw Peter's name on the police department applicant list and agrees not to tell anyone about it.
Gabriela tells Matthew that she is happy to be in his life, but as a friend. He thanks her for always being there for her and she says that won't change.
Mouch says goodbye to his girlfriend Mari and says he will visit her in Osaka when he next has some time off. She says that in her culture men with narrow eyes are destined for greatness and says that Mouch is going to do great things.
Joe Cruz says that Game Day is nothing to worry about. It's a big party tonight but it'll just go back to being a stale bar the next day.
At the station, Kelly receives a call from Renee but doesn't answer. Herrmann yells to Kelly that there is a problem with his car. Kelly runs out to see his car is on fire. When he gets near it explodes. There is nothing he can do now though. After the fire is put out they smell the same chemical as what they smelled at the house fire earlier.
Clark finds a homemade accelerant in the car. He has seen something like this before. Boden says they will bring an arsonist investigator to the station.
Later, Boden calls a meeting and announces the budget cuts. First up is overtime pay, it is suspended until further notice. They will double up their lockers and half of the locker room will store things from the closed firehouse. Otis jokes that he will share a locker with anyone but Cruz. Cruz volunteers to share with Otis. Boden also says that he believes Kelly is being targeted by an arsonist. It is also one year since Andy Darden died and he asks them to remember him and his family on this day.
Matthew stops by the restaurant to visit Heather. She introduces him to her friends and he buys them all a round of drinks before going back to work. When he gets back in the fire truck they are called to a fire.
At the house that is on fire, a woman says her mom is having chest pains next door. Gabriela and Shay move in to take care of her. The firefights find a woman in the burning house and help her out. Outside a strong wind blows and the fire jumps to the building next door. Boden calls Gabriela and Shay and tells them to get out of the building. They have an unconscious woman and can't get down with her. The firefighters send a ladder from the extinguished house to the burning house. Matthew climbs across with a hose and starts extinguishing the fire. Gabriela is sent across the ladder into the safe house. Shay is next to cross. Matthew says the fire is growing larger and they begin to pass the unconscious woman over the ladder on a stretcher. When Matthew crosses the ladder, the window sill in the burning building collapses and the ladder falls to the ground. Matthew holds onto the fire hose and is pulled inside. A fireman shows Boden and Kelly the fire starters that were found in the basement. They are identical to the one found in Kelly's car.
Back at the station, Shay apologizes to Kelly for what she said about Renee and their baby. She's back home visiting family so he wants to wait until she is back to confront her.
Otis is shocked when he sees some photos on Joe's phone. Herrmann comes over to see what is bothering him. There are photos and video of Cruz having a great time at Game Day. He apologizes for lying to them but he thinks it's the best bar on earth.
Gail calls Jeff Clark into her office and asks how he likes Squad 51. She says that she helped to get him his promotion and asks for him to be her eyes and ears for her. She asks him to check in once a week and let her know if anything is up. She makes a suggestion that it would be easy for him to go back to his old position and lose the promotion.
Mouch asks Boden if he has narrow eyes. Boden asks what answer Mouch wants to hear. Back at his locker Mouch looks at a picture of Mari and comes to a decision. He goes back to the main room where everyone is still fighting about Game Day. He rips down a poster of Greg Sullivan and announces that he is running for union president and would love to have their support. Everyone congratulates him and Herrmann says it is the best news he has heard all day. Their celebration is cut short when they are called out on an emergency.
They arrive at the scene of a DUI car accident. Matthew asks where the driver is and he is pointed to a nearby police car. It's Heather who is being arrested. She tells Matt that the kids are at the babysitter's and he promises to take care of them.