Truck and squad are called to aid in a massive all-city response when an old, ill-equipped factory-turned live/work space quickly turns into a firestorm, trapping countless unsuspecting victims. The dire situation quickly turns personal when it is discovered that one of Chicago PD's own has a family member at the scene. With the rescued victims in need of serious medical attention, the doctors and nurses of Chicago Med are tested as the major influx of patients are brought through their doors. Meanwhile, in the aftermath, the building owner steps forward to cooperate with the ongoing investigation, but the situation takes a sudden and unexpected turn.
When a turf war escalates, members of truck and squad find themselves caught in the middle as unsuspecting hostages when a group of armed gang members take cover and assume control over Firehouse 51. The situation turns even more dire when one of the infiltrators is wounded and in need of serious help.
When truck and squad are summoned to the scene of a dangerous accident, Chief Boden (Eamonn Walker) makes a split-second decision that overrides Chief Anderson (guest star Michael Hanrahan), the incident commander whose house was the first to respond to the call. Feeling his authority was undercut and his reputation damaged, Anderson uses his power to make things miserable for Boden and all of House 51 feels the repercussions. Meanwhile, Severide (Taylor Kinney) contemplates a major life-changing decision, Herrmann (David Eigenberg) does a good deed and Brett (Kara Killmer) looks to make some personal changes to herself.
After exercising his disdain and authority over Chief Boden (Eamonn Walker), Chief Anderson (guest star Michael Hanrahan) reassigns members of 51 to various houses around town, citing the need for improvement. The ramifications are felt by the crew, who are left to make the best of their respective situations in their new surroundings. Boden fights to repair the situation, but it just might be out of his control. Elsewhere, Severide (Taylor Kinney) toils over an important decision.