Severide and Dawson are at the place the fire took place last week. They conclude that an arsonist has been there and it's their lair. Severide asks Dawson to go with him to the scene of Shay's death as he isn't sure about the report about how the fire started. Dawson reluctantly goes with him and the discover the fire didn't start at the part of the building they thought it did and investigate further. They discover that it was an arsonist attack. Shay was murdered.
The team are called out to a head on collision and realize the Chaplin is involved. Both victims are taken to the hospital, but the Chaplin is in a bad way. The hospital can't find a next of kin for him and Casey sets out to. In the end, the Chaplin wakes up and begins to recover.
Mills and Brett are called out to a head injury victim, but are shocked when she refuses treatment. It appears her husband is telling her not to accept it. Brett and Mills think this is domestic violence. Later, while dropping off a guy who cut his fingers off, they see the woman again, battered and bruised. Mills attacks the husband and threatens to kill him if he touches the woman again,