Intelligence begins investigating the Med patients who were misdiagnosed with cancer and given an overdose of chemo.

They discover the doctor doing this might be the same doctor Hank's wife went to before she died. Lindsay and Halstead go to question him.

Roman's shooting is being investigated and he is suspended. 

Voight arrests Dr. Ribold for obstruction of justice. 

Burgess is looking into Roman's shooting. 

Intelligence finds several other cases of patients unnecessarily treated with chemo. The DA wants to make a deal for fraud but Intelligence wants him charged with homicide. She says they need new evidence. 

Voight talks to Dr. Charles who tells him Dr. Ribold is a psychopath. They learn one of the patients, Jessica Pope, died. 

Burgess questions Richie's brother, thinking he may have taken the gun to frame Roman. 

Dr Charles talks to the doctor in a coffee shop.

They find evidence that Dr. Ribold ordered too much chemo and didn't submit it to insurance. He murdered four women to cover up his fraud. They arrest him on murder charges. 

Burgess brings Platt to question Richie's brother, Denny. They convince him to make an anonymous tip to the gun's whereabouts for the reward money. 

Voight takes the stand in Dr. Ribold's trial and says he witnessed him giving chemo to his wife. Dr. Ribold is found guilty of murder.