Severide and Stella keep an eye out for Grant; Louie has Dawson questioning her dangerous career path; Casey's relationship with Susan Weller cools down; tensions between Borrelli and Boden reach a boiling point.
Casey and Dawson get caught in what may be a political mess; Stella has a big decision to make about her boyfriend; members of the squad are in a dangerous situation after responding to a car accident; Severide befriends a famous socialite.
Casey gets help from Susan Weller for an urgent personal matter; Severide is given an opportunity to travel with Travis Brenner; Stella saves a street kid from a tunnel fire.
Casey is forced to use extreme measures to save a father and daughter from an acid spill; Dawson and Brett respond to an elderly woman who has a difficult senior advocate; Otis shares some exciting news.
Casey is unable to save a woman trapped in a burning house; Herrmann is determined to catch a mysterious tagger that targets the firehouse; Boden has an unexpected visitor; a teenager is injured during a romantic proposal.
Dawson faces repercussions after she hits a pedestrian with the ambulance en route to a call; Casey and Severide continue to investigate an arson case; Chief Boden must decide whether to attend an important event in New York.
Things don't go as planned when Dawson and Antonio's parents come to town for their anniversary; Chief Boden deals with his stepson James' secret; Casey tries to save a young boy during a call to a warehouse; Otis and Kidd become competitive.
Casey and Dawson run into a problem when they apply to permanently adopt Louie; Jeff Clarke gives an interesting proposition to Severide; Otis persuades Herrmann to throw a party at Molly's to celebrate the bar's 100th anniversary.
Dawson and Casey face legal issues as they try to retain legal guardianship of Louie; Severide continues to look for a bone marrow procedure to help Anna; Brett opens up to Dawson.
Severide agrees to a bone marrow donation; Casey and Dawson attempt to find harmony at home; Otis and Mouch plan to create a PSA to encourage people to join the Chicago Fire Department.
Dawson struggles to control her emotions during an ambulance ride with a pregnant teen; the firefighters rush to a building fire; Casey must make a quick decision when two victims both need life-saving assistance; Severide shares a bond with Anna.
A dangerous man is on the loose with a vendetta against Lt. Casey and the Firehouse 51 squad; Antonio's ex-wife appears; Casey has a gift for Dawson.
Chief Anderson feels his authority was undercut after Chief Boden makes a decision that overrides Anderson's when both squads respond to the scene of a dangerous accident; Severide ponders a lifechanging decision; Herrmann does a good deed.
Citing a need for improvement, Chief Anderson reassigns members of 51 to other firehouses, leaving the crew members to make the best of their respective new situations; Severide struggles with an important decision.
Fire and rescue are called when an old warehouse-turned-work space turns into a firestorm, trapping countless victims; the doctors and nurses of Chicago Med deal with a barrage of patients as victims of the disaster are brought through the doors.
Members of the fire and rescue squads become hostages when a group of armed gang members invades and assumes control over Firehouse 51 during a turf war.
A series of similar car accidents raises suspicion that someone may be targeting innocent people; Severide tries to make Anna feel welcome in her new Chicago surroundings; a persistent constituent asks for Alderman Casey's help in resolving an issue.
Casey discovers a new crack house on the block that's harboring a female junkie; a new trainee gets Dawson and Brett into trouble; Severide gets an unexpected visit from his father.
Casey reunites with a former colleague; Dawson and Brett serve their time in retraining; Severide tries to fix what's going on with Anna.
Casey takes extreme measures to help his friend Kannell; Severide helps an old widow come to terms with letting go; Otis and Cruz find a new roommate.
Mouch offers to help when an off-duty incident puts Cruz in a bad spot; Casey takes on a powerful politician; Lt. Severide makes life difficult for a new team member; Dawson gets an unexpected visit from her father.
A warehouse blaze puts the fire and rescue squad at risk; Dawson's father overstays his welcome at Dawson and Casey's home; Casey fights for his first responders bill; Mouch makes a serious decision; Herrmann tries to make a young boy smile.