A group of protesters attempt to lock down Firehouse 51 just as the firefighters are on the way to respond to a call.
The ringleader Lewis says they're protesting the closure of their district's firehouse and decided to make their last stand at 51.
More protesters join them, and the Chicago Police Department gets involved.
The Chicago Fire Department sends someone from headquarters but that only makes matters worse.
Casey reaches out to the district alderman, but things still go poorly.
Afterward, Lewis, who is chained to the rigs, needs medical attention, and 51 works to save his life.
The rest of the protesters are then removed.
Boden visits Lewis in the hospital and tells him the city will work to reopen Firehouse 87.
Brett is still grieving the loss of Julie when Scott asks Brett to talk her half-sister.
If not, Scott says he'll put his daughter up for adoption.
Brett is later able to convince Scott to keep his daughter.
Gallo and Ritter create an Instagram account for 51 and want to tell the protesters' side of the story, but Boden prohibits them.
Boden eventually comes around, and their post is one of the reasons the city changed its mind.
Cruz finally gets married to Chloe in a chapel.