Lt. Casey returns to work at Firehouse 51 after nearly being killed in a building collapse and Shay meets Allison Rafferty, her new partner, who is friendly to everyone except her. Dawson begins her rigorous training at the Chicago Fire Academy, while Lt. Severide prepares for his stint as instructor. Meanwhile, Clarke stubbornly does not speak with the police about the murder in which he is the prime suspect and the future of Molly’s looks bleaker than ever.

Lieutenant Casey 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, 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 and Katie bond over board games, Boden helps out a woman with a negligent landlord and Dawson notices fellow recruit Rebecca Jones undertaking some interesting test-taking techniques at the Academy.

Severide feels sidelined as he leaves Detective Lindsay and the Intelligence Unit to do their job and locate his sister Katie. Shay gets an unusual tip from Chicago Blackhawk players Brent Seabrook and Duncan Keith, who makes friends with Clarke and stop by Molly’s. Meanwhile, Casey learns more about his head injuries after another close call and Dawson pushes hard to pass the physical test at the Academy.

Severide is getting impatient with the police as Vince Keeler walks free. Meanwhile, the house pulls out all the stops to save a girl trapped inside a donation bin, Mouch learns that Boden’s secretary Connie is not someone to mess with and the squad and truck are called to a serious high rise fire inside a 20-story downtown office building.

Lt. Severide hits the top of the list as Det. Lindsay starts calling in suspects with the clearest motives to make the guy who kidnapped Katie disappear. Meanwhile, Jones is still having trouble fitting in as word of her disruptions reach the fire department’s headquarters. Elsewhere, Herrmann celebrates his twentieth anniversary with his wife, but no one supports his idea on the gift he intends to give.

Lt. Severide is reminded of his own past by a man he saves from a car accident and feels compelled to help him. Elsewhere, Lt. Casey and Chief Boden grapple with how to dock Jones per her father’s orders. Meanwhile, Mouch and Dawson have troubles with the opposite sex and an emotional call to duty creates ripples throughout Firehouse 51.

Lt. Severide sticks his neck out for Dave Bloom, a fellow firefighter from Denver who is troubled by addiction. Elsewhere, Dawson and Shay leave town for a "girl's weekend" at a cabin in the woods. Meanwhile Jones struggles with the knowledge that her father is pressuring Chief Boden about her career path and Mouch's internet dating profile gets an upgrade with the help of Mills and the guys.