Tim Hopper

Izzie faces her past and finds comfort in George, while Alex becomes more attached to Jane Doe (Elizabeth Reaser), Meredith and Derek question their own status, and Cristina resolves to fight for her relationship with Burke -- despite her past with Colin Marlow (Roger Rees).

Casey struggles with his new responsibilities; Severide dreads the arsonist's next attack; Mouch starts campaigning; Dawson and Shay decide they need to get out more.

Chief Boden turns up the pressure on Severide and Casey to investigate the cause of the fire that trapped his wife; Mouch is over-competitive in the firefighter muster challenge.

Members of Firehouse 51 are dismayed to learn their boundaries have been redrawn to overlap with an adjacent station, and problems quickly arise; Casey and Gallo hunt a missing piece of equipment; Brett and Foster find themselves at odds.

A major security breach in the city’s computer networks forces Firehouse 51’s senior leaders to take matters into their own hands. Severide gears up for an arson investigation.

Gallo clashes with the new lieutenant temporarily filling in for Casey; Severide closes in on a dangerous and deadly arsonist.