The big wedding day arrives and Firehouse 51 welcomes Casey back to celebrate the joyous occasion. Emma’s plans to replace Violet come to a shocking end.

A family friend asks Herrmann for some advice on opening a bar. Tensions run high between Emma and Violet. Kidd struggles to keep her team together.

A video of Casey from the roof rescue goes viral. Mouch sets up a Little Free Library at Firehouse 51. Herrmann breaks protocol.

Mouch and Ritter work together to solve a murder mystery. Severide and Cruz tackle a food truck fire. Gallo goes to see Hawkins about Violet.

Boden, Kidd and Severide work together to protect one of their own. At the Fire Academy, Herrmann meets an inspiring young man. Talk of the annual CFD Gala dominates the…

All seems lost with firehouse 51 on the verge of closing its’ doors, thanks in no small part to Gail McLeod, but Chief Boden and the rest of the house…