Brett and Foster respond to a call at a juvenile facility. A young teen named Isaac was brutally beaten, but the guards don't want them to check him out at first They are eventually are allowed through the have to take Isaac to the hospital, but before he can tell them the truth about what happened, a guard joins them and he clams up.

Brett suspects that the guards are being abusive. She runs it best Boden who gives his support. She and Foster go to see Isaac's mother but she's less concerned.

Brett takes it up with the head of the facility, but they are backing the guard. A social worker offers some information that confirms the guards are probably being abusive. The facility is protecting the guards and bring Isasc in after threatening him to make sure he isn't filing a complaint.

Isaac lets them know he's being threatened and the other kids start telling them what the guards do to them. Brett threatens to have them all arrested if they harm the kids again.

Boden wands Stella to get her scuba certification. Severide helps her prepare

Gallo starts his first shift at the station. Cruz gets annoyed when he almost takes Otis' locker. Boden still has reservations about the kid being too reckless and not knowing how dangerous the job is.

He proposes a risky save procedure on a case involving a ferris wheel. Casey backs him and it works, but Boden warns Casey about Gallo. Gallo shares why he wanted to be a firefighter with the squad. He was in a fire as kid. But later Boden talks to his friend who mentored Gallo and finds out that his whole family died in that fire and that Gallo hung around the fire station all the time and was looking got a family.

A tech rep sets up electronic everything in the station. Casey sleeps with the tech who researched him and is enamored.

When the new system spends all day blaring and no one makes it out to fix if, Boden throws it outside and breaks it. When the tech finds it, she's upset, and tells Casey to lose her number.