Lindsay and Halstead respond to a shots fired call and find multiple dead bodies and a young girl still alive.
Roman is in rehab and nearly ready to return. He asks if he and Burgess will still be partners and Platt tells him it's a sticky situation.
Lindsay wants to stay at the hospital until the girl wakes up. Halstead wants her to go home and sleep.
Autopsy shows the dad received a beating three months ago.
Olinsky and Antonio follow a lead on Horizons, a pyramid scheme group the couple was involved with.
Polly, the survivor, attacks someone in the hospital. Lindsay gets her to drop the knife, but Dr. Charles won't let her talk to her further yet.
Platt tries to convince Crowley to let Burgess and Roman remain partners, but she refuses.
Dr. Charles and Lindsay talk to Polly. She says she needs to go to the house on the lake. They don't know if the house exists.
Roman is told his condition is most likely permanent and he can't return to the streets safely.
Halstead finds the house. He, Lindsay, and Polly go check it out.
The team arrests a suspect, Gerald. He committed statutory rape with one of the daughters.
Polly says it's someone older. She ID's Lewis from a photo and they go to arrest him. He starts shooting. They catch him.
Roman asks Burgess to move to San Diego with him.