Karen Aldridge

At the site of a train accident, Peter Mills becomes deeply upset when he observes the dead body of a young victim. Unable to shake his emotional distress about the event, he questions his future as a firefighter. Dawson and Shay save a 6-year-old girl whose mother is abusing her – but their confrontation leads the woman to resort to dire actions. Meanwhile, Severide aggravates his injury while rescuing a heart attack victim and Shay sends Clarice, her married, pregnant ex-girlfriend, back home to her husband.

Lieutenant Casey (Jesse Spencer) tries to convince himself and everyone around him that he is one hundred percent healthy following his near-death incident in the line of duty. Shay (Lauren German), not wanting to delve into the emotionally traumatic incident, continues to elude a lawyer who wants to speak with her about Daryl's suicide. Meanwhile, Otis (Yuri Sardarov) and Katie (guest star Brittany Curran) bond over board games, Boden (Eamonn Walker) helps out a woman (guest star Melissa Ponzio) with a negligent landlord and Dawson (Monica Raymund) notices fellow recruit Rebecca Jones (guest star Daisy Betts) undertaking some interesting test-taking techniques at the Academy.

Lt. Casey (Jesse Spencer) and Dawson (Monica Raymund) volunteer to help at a charity run at Chicago Medical when a massive explosion sends Chicago into chaos. With one of their own missing in the blast, the firehouse is tested like never before.

Frank faces public backlash after an officer's body camera malfunctions during an altercation with a civilian. Meanwhile, Danny and Maria struggle to protect an informant after the U.S. Marshall's Service decides not to put him in Witness Protection, and Erin investigates an old friend's daughter's claim of rape at a prestigious university.

Dawson (Monica Raymund) starts her first day as a candidate and looks to find a balance with Lieutenant Casey (Jesse Spencer) inside the firehouse. Mills (Charlie Barnett) must come to terms with a future that doesn’t include the squad. Meanwhile, Severide (Taylor Kinney) confronts his demons in an unexpected way and the Molly’s crew has a date with the city inspector to make sure their food truck is up to code.