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.
Cruz forms a bond with a young immigrant boy he meets while fighting an apartment fire. Squad makes plans to prank the newest member of their team. Hawkins and Violet struggle to keep their relationship a secret.
Firehouse 51 must band together when one of their own is taken hostage.
Severide and Kidd work with CPD regarding a suspicious car wreck. Hawkins and Violet's relationship is in jeopardy. Chloe and Cruz adjust to a new family dynamic.
Following an injury in the aftermath of an industrial fire, Severide and Seager work together to investigate an anonymous tip. Kidd searches for the right person to fill the open spot on Truck 81. A possible new recruit to 51 gets tested at a call.
