The members of Firehouse 51 and the Austin firehouse clash when trucks collide on the way to a call; Boden comes up with a plan to get Dawson her badge; Mills faces his past and future; the Molly's group hits a speed bump starting the food truck.
Boden pushes his team to pull it together in the aftermath of the explosion; Casey works to track down a missing Severide; Newhouse brings news about one of Mills' relatives; Herrmann and Otis come up with new goals.
Severide comes back to work, but isn't his usual self; Mills discovers more information about his father's family; Herrmann asks Molly investors to share ideas that could help turn the business around.