A fire at a homeless encampment leaves Severide and Casey searching for answers. Cruz is shaken up after a close call. Ritter lends a helping hand to a victim.
Gallo makes a split-second decision during a dangerous fire rescue leaving Casey steaming that his direct orders were not obeyed. Kidd feels a strain in her relationship with Severide. Brett and Mackey find themselves searching for answers following a series of suspicious calls.
When Firehouse 51 is called to the scene of a dangerous blaze inside a 10-story storage unit, Herrmann and Cruz find themselves trapped inside a freight elevator with all communications cut off.
While completing a task assigned by headquarters, Boden makes an unforeseen connection. Gallo is forced to make a surprise rescue to one of their own when the firehouse is called to the site of a construction explosion. Mouch reignites an old feud.