Casey struggles with his personal life problems, and the fire department welcomes a new member.
The team tries to put out a fire that swept through a residential complex, confining its victims to the upper floors.
Severide tries to rescue a captive child from a car wreck and faces a difficult situation.
A series of bombings hit Chicago, and Hermann adjusts to his new duties.
Casey investigates the cause of a fire at a trailer park.
Brett and Foster try to deal with a devastating disaster after a Halloween prank turns tragic.
Severide tries to deal with the tragedy of his father's death, and Brett suspects a teen driver in a car accident is hiding something.
Fire Department 51 responds to a call for help to extinguish a fire that puts everyone in danger.
Brett and Foster respond to a horrific call, while Severide and Kidd find their relationship tested.
Casey and Naomi flee a deadly fire that breaks out in his apartment.
Brett tries to help Casey find a new apartment after his apartment catches fire.
The fire brigade is called to a motorcycle crash.
Cruz is responsible for managing the fires and organizing the annual Polar Plunge event.
Brett, Foster, and Kidd take a road trip to Indiana and deal with an incident involving members of the hockey team.
A fire station box goes missing, a series of thefts occur, and suspicion falls on one of the firefighters.
Casey struggles after experiencing a lot of chaos after receiving a distress call.
Tensions grow between Casey and Hermann after responding to a fire at an apartment complex.
Severide becomes angry when he feels that his orders are not being obeyed during field work.
A devastating storm breaks out in Chicago, causing chaos and fires, affecting Fire Station 51 as it loses power.
Severide and Boden investigate whether a fire at a hair salon was caused by arson or not.
An old case of a man responsible for a series of fires is opened after Severide finds evidence linking him to the salon incident.
Severide and Kidd continue to investigate the unsolved serial arson case.