Continuing the story from Chicago Fire Season 5 Episode 9, Kelly Severide is the prime suspect in a car accident that injured a woman and killed her daughter. Lindsay refuses to believe that Severide is guilty which causes tension between her and the rest of the Intelligence Unit, especially Halstead.
The squad finds out that Severide did get his car keys from the valet at the bar and that his blood alcohol level was twice the legal limit, making him look guilty. But when a tracking device is found on the Mustang other suspects emerge: a crew of car thieves who just had their eyes on Severide's wheels.
CPD uses one of Atwater's sources to identify the leader of the theft ring as a man named Michael, and has him lead them to Michael's base of operations where they take him into custody. From there it's easy to identify the real driver and they use his mother to bait him into custody.
Meanwhile Burgess arrives in Intelligence and is partnered with Olinsky, who is less than thrilled with the assignment. He asks for her to be reassigned but Voight refuses. And Lindsay ponders whether or not she should meet her father while finding out that Voight "ran into [him] a couple times" in the past.