Jay Halstead took little time to mourn his father's death following the deadly fire that brought One Chicago shows together for the latest crossover event.
After injuries from the fire led his heart to give out and ended with his father being brain dead, Jay was determined to focus on helping the Intelligence Unit solve the mystery of who started the fire, lashing out at his friends and loved ones as he did it.
After the team realizes that a gang-related hit caused the fire, Jay becomes even more enraged about what happened and puts himself at the forefront of the investigation. The new information leads the team to a cartel driver, who they plan to arrest at his home.
The plan involves the team going into the house while Jay stays in the back door and covers them. When Upton (Tracey Spiridakos) enters the kitchen, she is startled when she finds that Jay is already in the house and apprehended the man himself.
Back at the station Voight (Jason Beghe) and Antonio (Jon Seda) show the man photos of the people who died in the fire, including Jay's father. Outside the interrogation room, Upton tries to console Jay but he responds by saying his relationship with him was not great in the first place, so he won't be sidelined in the case because of his death.
"Look, my father and I, we never clicked," Jay told Upton. "He didn't want me to be cop. Guy didn't even show up when I graduated from the academy. He was embarrassed. So, I learned to keep my distance, now he's gone. Im learning to deal with it on my own, you don't have to question if I'm alright."
Further investigation leads the team to the man's son, Daniel, who they find out was the man who started the fire, in an attempt to cover his murder of a cartel leader. When they attempt to find the man's safehouse they realize it's a trap.
The house doesn't seem to have explosives, as Severide (Taylor Kinney), the fire department and the bomb squad determine. He tries to talk to Jay, but he lashes out saying he doesn't need anyone else to give him "half-assed" condolences. Severide tells him instead that if he can help in any way with the investigation he wants to, given Stella's (Miranda Rae Mayo) injuries.
His help comes in handy later in the episode, when in an attempt to find Daniel, Voight tells Jay to stay behind without car keys so he can't follow them to find the suspect. Upton tries to comfort him after Voight's orders but he yells at her and tells her not to project her own issues on his grief. After the tense moment, Jay calls Severide and has him drive him and capture the radio frequency of the cops so he can follow the lead to Daniel himself.
He ends up finding Daniel first and gets shot in the process, but the bullet luckily does not go past his bulletproof vest.
After the suspect is dead and Jay is given the all-clear to go home, he and his brother Will (Nick Gehlfuss) go to their father's house. He goes into his room and finds some old photos of the family, and among them he sees his father kept a photo of his police academy graduation, along with newspaper clippings from one of his biggest rescues as a police officer.
At the realization that his father was proud of him and loved him very much, Jay breaks down and feels the loss of his father for the first time.