Erin takes Bunny's information to Voight who says it will all be dealt with by the books so they will be taking a statement from her.
Lindsey and Halstead go on the look out and find a man taking a woman hostage at a bank. They try to get him out the building with tear gas, but they have to shoot him. He survives. The hostage says they have her family somewhere and are threatening to kill them.
Voight and Lindsay then go to the hospital and wheel the suspect out to get the name of the person holding the family hostage. Voight knocks him into the snow and they get a name, Milo.
The team find the truck in the water with the bodies of the family. They have drowned. After a lengthy game of cat and mouse the team catches Milo, but he is killed as they are taking him to the station.
Antonio reconnects with an old colleague who he used to have a thing for.
Linstead continue to debate whether to inform Voight of their relationship. Voight puts his life on the line to bail Bunny out when it emerges she only informed of the case for the reward.