In the season finale, a boarding school fire leaves Severide shaken as Boden's grand plans take a detour.
The firehouse pulls together to help Dawson retake the firefighters' exam; the station welcomes a new squad member; Shay receives an uninvited guest; Boden makes a bold move.
A massive explosion sends Chicago into chaos - and 51 to the rescue.
Firehouse 51 struggles to cope after the tragic death of Rebecca Jones; Severide performs one final gesture for Bloom; Boden seeks to reconnect with Donna.
Jones fights to stay on at Firehouse 51 while Dawson and Shay take a girls' weekend at a remote cabin.
A father's heroic sacrifice affects the entire squad - and leads to an unexpected threat.
Keeler's disappearance ignites an investigation into everyone with a motive from Firehouse 51.
With Keeler a free man, Severide takes matters into his own hands.
Severide and Chicago P.D. hunt for Katie while Dawson faces the final test of her training.
Firehouse 51 steps in when a blackout causes chaos during a frigid night in Chicago.
Casey continues to deny his lingering injuries; Shay receives stunning news about Darryl's suicide; Dawson struggles to keep a damning secret.
Dawson faces an uphill battle - and unlikely competition - as a new recruit at the academy. Meanwhile, Casey discovers a lingering injury and Mills receives life-changing news.
On the verge of closure, Firehouse 51 bands together in a fight to save the station.
Dawson and Casey's romance escalates while Shay hits rock bottom and goes MIA.
A drive-by shooting forces Cruz to make a big decision while Casey and Dawson struggle to keep their feelings at bay.
Firehouse 51 is thrust into the furnace with a train derailment.
In a touching ceremony, Chief Boden and Donna get married at Firehouse 51.
Sound mixer Blair Scheller talks about miking a house fire and isolating dialogue.
Chicago Fire arrives on a scene to put out a stove fire, but find the person responsible in a bizarre location and position.
The actor chats about Mills' father and the future of Chicago crossovers.
Lauren and Monica talk about how long it took to shoot "No Regrets".
David Eigenberg and Eamonn Walker answer fan questions from Twitter.
The Fire Fighters arrive on the scene to find that a car has crashed into a home, and a baby and mother are trapped inside.
A major explosion occurs at Chicago Medical, where Casey and Dawson are volunteering at a charity run.
Joe Minoso and Charlie Barnett compare Pouch to Top Dog winner Smokey and talk the importance of firehouse dogs.
Casey races against a raging fire to save himself - and a rescued baby - from certain death.
Go behind the scenes of Leon's car crash with stuntman Dan Maldonado.
The Firefighters arrive on the scene of the biggest fire this season.
Executive Producer/Director Joe Chappelle discusses what makes the premiere a "super episode."
Severide leads the squad into another dangerous building fire, only to find a familiar face watching them from across the street.
Taylor talks about his role.
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