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.
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.
Firehouse 51 tackles a fire caused by a dropped jet engine and one of their own is accused of a theft related to the incident. Kidd and Boden disapprove of Kylie's potential new love interest.
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.
