Katherine Cunningham

Severide is hiding a serious shoulder injury sustained in the fire that killed Andy Darden, and grapples with his guilt as he fights to rescue a construction worker trapped in a building collapse. Adding to the burden, Darden's wife Heather turns on Severide at the annual firefighters' barbecue, blaming him for her husband's death. A call is made to an accident site at Hancock Tower, where two teenagers are pinned in a vehicle trapped beneath the falling debris of a broken window washer's cart. Meanwhile, Casey and Hallie work to figure out their future together.

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.

After he's injured in a terrible fire at an auto machine shop, Jose Vargas is forced to go on disability and leave his life as a firefighter behind - a task he finds incredibly difficult. Chief Boden tries to help a suspected teenage firebug. Also, Severide receives an enticing invitation from Renee, a woman who he saved from a car crash incident involving live electrical wires. Meanwhile, Cruz tries to save his younger brother Leon from the gang he is involved with.

Meredith heads up a pro bono surgery day, but the overwhelming patient response causes her to struggle to keep things in order; DeLuca treats a teenage patient whom he suspects is in danger.

To carry out a sailor's dying wish, Gibbs and the NCIS team re-investigate a murder case that was originally ruled an accidental death. Also, the case reminds Torres of a tragic time from his past.