Casey and Hallie are back together and better than ever. Dawson spots the happy couple outside the station and seems confused by her feelings. On the one hand, she knows she's happy with Mills. On the other hand, she also feels a little jealous of Casey and Hallie's reconciliation. Mills chooses the worst time to complicate things by inviting Dawson to move in with him. It's a huge decision and she'll have to think about it.
Before Dawson has time to reflect on the conversation, a call comes in and she and Shay hit the road. On the way, she confides in Shay that she feels guilty for not telling Mills that his mother had a relationship with Boden in the past. The squad arrives at the scene of a balcony collapse in which dozens of college kids are trapped in a pile of sharp wood planks. They systematically pull the kids out of the rubble.
Boden talks to Severide in the bathroom about confronting Tara, the girl who is accusing him of sexual assault. Boden assures Severide that he's just trying to help, but that if he attempts to contact Tara again, he'll take away Severide's position as Squad Leader. Severide takes offense and tells Boden that he'll handle it himself.
In the ambulance, Dawson tells Shay that she's trying to look at the bright side of things, get over her concerns about Casey and appreciate Mills more. Back at the station, Severide confides in Shay about his issues with Tara. Shay suggests that Severide go on the offensive and look into Tara's past, because this is probably not the first time she's accused someone of assault for personal gain.
After their shift, Mills and Dawson meet up for a date. Mills is troubled that, when he told Dawson that he loved her, she didn't say it back. Dawson assures Mills that she loves him too and that she's excited to move in with him. It's exactly what he wanted to hear.
Severide meets with Antonio, who helps by pulling some information on Tara from the police files. Severide learns that Tara pressed similar charges against another man a few years ago, and decides to investigate. He tracks down Clay White, a former co-worker of Tara's who was also accused of assault. It seems Tara has a pattern of false accusations. Severide enlists Clay to help in his case.
Casey stops by the clinic where Hallie has been working. It's full of injured patients, but Hallie loves the environment, and Casey is happy to see Hallie content with her work. The next day, after a daring rescue at a hellacious car accident, Severide and Clay corner Tara in her work cafeteria and threaten to expose her pattern of false accusations. Tara reluctantly agrees to drop the charges against Severide.
Back at the station, Herrmann introduces Chief Boden to a visitor, a 12-year-old girl who tells the chief she was left on the steps of the station as a baby, and Boden was the firefighter that rescued her. It's a heartfelt moment for the Chief, and a pleasant reminder that sometimes his job can be rewarding. Later in the locker room, Otis discovers that Mouch has a Japanese internet girlfriend.
Chief Boden informs Severide that Tara Little has resigned from her position and dropped all charges against Severide. Severide says he understands the Chief was just looking out for him, and he assures Boden that his methods of persuasion were perfectly legal.
Dawson pulls Mills aside to tell him what she knows about Chief Boden and Mills' mother. She explains that she wants to be honest with Mills in order to strengthen their relationship, but Mills is upset that Dawson didn't tell him sooner. The relationship instantly becomes rocky and uncertain. Before anything can be resolved, they're called to the scene of a fire, and it's at Hallie's clinic.
Upon arriving at the clinic, Casey immediately notices Hallie's car in the parking lot. She's trapped inside the inferno. He rushes into the flames without hesitation. The other firefighters pull survivors out of the flames while Casey frantically searches for Hallie. Eventually he finds her unconscious in the back of the clinic, and he and Severide barely drag her to safety.
Hallie is badly burned and not breathing. Dawson struggles to revive her in the ambulance before she's rushed into the emergency room. Later, the doctor comes out to inform Casey that Hallie didn't survive. It's a crushing blow to the entire squad, and especially to Casey. Today, they've lost one of their own.