Gallo makes a split-second decision during a dangerous fire rescue leaving Casey steaming that his direct orders were not obeyed.

Casey lays into Gallo for disobeying orders and sends him home.

Casey later talks to Gallo and explains that by Gallo making such an impulsive move robbed Casey of his accountability.

As an officer, Casey is responsible for Gallo's safety and tells Gallo this can never happen again.

Gallo agrees.

Kidd feels a strain in her relationship with Severide and considers postponing taking the lieutenant's exam.

Kylie, in turn, tells Severide about Kidd's consideration, and Severide comes clean to Kidd about why he was keeping his distance.

Kidd tells Severide that she doesn't care what the CFD brass are saying; she just needed her boyfriend to reassure her that she could do this.

Severide does, and the couple makes up.

Casey sleeps with Sydney, and they go out again, prompting Casey to realize he's still hung up on Brett.

Brett sees Casey's interactions with Sydney as him having moved on, and Mackey suggests Brett get out there.

Cruz and Herrmann hide the news that Chloe is pregnant, and Mouch believes they are talking about him.

Mouch later reveals he got a tattoo of Trudy's name on his butt after he lost a bet.

Gallo and Mackey sleep together.

 Brett and Mackey find themselves searching for answers following a series of suspicious calls.