"Arrest in Transit"

Dawson and Casey aren't doing so good, they are trying to make the lieutenant/candidate thing work and it’s not working out too well.

On their first call, the team deals with a chemical spill. When Dawson breaks protocol to create a perimeter, another chief happens to pull up on the scene and sees that Dawson wasn't wearing protective gear. Casey’s ticked, especially when Boden tells him he’s got to get it under control.

When Casey talks to Dawson, he raises a very good point. Dawson continually breaks protocol, which might have been more acceptable as the PIC. But not as a candidate. Casey tells her, “Following orders is not up for debate…If it happens again, I’ll be forced to kick you off Truck.”

Mills finds Dawson sitting in the shower (fully dressed) crying, when he asks whats wrong she tells him shes debating on taking a shower or not. He knows something is wrong and really wants to help her.

On their second call, a desperate husband goes crazy trying to get his wife out of a burning building. When she’s found, he jumps off the stretcher and runs to her. When Mills calls him crazy, Herrmann says, “That’s marriage.” Dawson and Casey look at each other and it’s clear they are not feeling it.

Meanwhile, Severide and Brittany go on a run together, and she avoids a call from her mom. When Severide suggests they go see her family for Thanksgiving, she says no. Brittany asks to see a picture of Shay and asks Severide why he never talks about her. “You never talk about Kathleen. I kind of thought that was the deal,” he says. When Severide takes Brittany to a museum about the Chicago Fire and the history of the department, she breaks down and tells him that she was driving the car when her sister Kathleen was killed. She walked away from the accident with a few stitches, but her sister didn’t make it.

Brittany tells Severide that she has to go home to her parents in Florida. Severide tells her that he has been using Brittany as a coping mechanism so that he didn't have to deal with Shay's death. But he needs to deal with Shay's death on his own and Brittany needs to go home and deal with her sisters death with her family.

Turns out after all of the cooking and Zumba together Cruz is falling for Brett. When he asks her out she panics and tells him they are better just being friends.

Mills and Brett are on the scene for a high school student, Jason, who drowned in a school pool. He’s revived on scene, but taken to the hospital just in case. All seems to be fine but on the way to the hospital, Jason crashes and is pronounced dead at the hospital. Of course, Jason’s dad turns out to basically be the head of the Chicago mafia. He points out that his son was alive when he went into the ambulance and blames Mills for his son’s death. The dad shows up at the firehouse after shift and tells Mills, “You’re dead.”

At the end of the episode Brett decides to go on a date with Cruz.

Dawson stays late at Molly’s to close, and Mills stays late because he is afraid the mafia might be near. They clean up together and then have a beer. He asks her how she’s doing, knowing that she’s struggling. Dawson tells him that things between her and Casey aren't great, even admitting that their home life is on the rocks. He puts his hand on hers and then, Casey walks in and sees everything.