Lindsay is meeting with a Dr. Charles until she is called away.
Voight and Lindsay find out that Bunny is saying Voight lied about witnessing a murder. She claims she can prove he wasn't on the scene.
Sgt. Platt is overwhelmed by a crowded station. A distraught man is upset she's not listening to him when he says his 18 year old daughter is missing. He pulls a gun and takes Mouse hostage.
Lindsay confronts her mother, but it doesn't go well.
The team investigates the missing daughter by following the trail of her stolen credit card. They find a house with girls locked up in cages.
Lindsay questions one of the girls in the hospital about the guy who did this to her. She shows her a picture of Sarah and she recognizes her. Lindsay brings her to talk to Sarah's father and she tells him Sarah is alive. Mouse gains the upper hand and they arrest him.
They arrest Trevor Dunn at the bus station and question him about Sarah. Voight beats him to get him talking. He says he's just the middle man and gives Voight the name of the guy in charge, Ulrich.
The guy Voight lied to put away, Beckett, is being released.
The team finds Ulrich dead and follow another lead to a train where they find Sarah holding a gun, threatening to shoot herself. Lindsay has Voight bring her father.
The gun Frazier used wasn't loaded, reducing his charge. Mouse unloaded it.
Olinsky's daughter stops by Antonio's boxing gym. Olinsky finally tells his family about her. His wife asks him to leave.
Voight's car blows up as he and his family are about to get in it.