On the verge of closure, Firehouse 51 bands together in a fight to save the station.
All seems lost with firehouse 51 on the verge of closing its' doors, thanks in no small part to Gail McLeod (guest star Michelle Forbes), but Chief Boden (Eamonn Walker) and the rest of the house refuse to allow themselves to sit by and let it happen. An emergency call to an apartment structure fire tests everyone's limits and puts the squad in harm's way. Meanwhile, Dawson (Monica Raymund) receives some life-changing news and union president Greg Sullivan (guest star Eric Slater) makes headlines, which has an immediate impact on Mouch (Christian Stolte).
The Firehouse is set to close, but 51 is not going down without a fight.
Dawson and Casey's romance escalates while Shay hits rock bottom and goes MIA.
Battalion Chief Boden (Eamonn Walker) prepares to counterattack McLeod (guest star Michelle Forbes) in a final effort to save the firehouse from closure and the romance between Dawson (Monica Raymund) and Casey (Jesse Spencer) escalates. Leon (guest star Jeff Lima) is making progress in the gang murder investigation, but Cruz (Joe Minoso) cannot stand being left in the dark by Voight (guest star Jason Beghe), fearing for his brother's safety. Meanwhile, Severide (Taylor Kinney) and Katie (guest star Brittany Curran) bond to make up for lost time and Otis (Yuri Sardarov) feels uncomfortable living with Severide and Shay (Lauren German) after Devon's (guest star Vedette Lim) latest escapade.
Boden is left to wonder where things stand for Firehouse 51 as McLeod exerts her influence.
A drive-by shooting forces Cruz to make a big decision while Casey and Dawson struggle to keep their feelings at bay.