When a DUI suspect is brought into Med with critical injuries, Dr. Rhodes (Colin Donnell) must operate immediately to save the suspect's life. After refusing to allow a police officer to draw blood from the suspect before the surgery, Maggie (Marlyne Barrett) is arrested and led out of Med in handcuffs. Goodwin (S. Epatha Merkerson) reaches out to Voight (Chicago P.D.'s Jason Beghe) to explain the situation - after all, Maggie was only following hospital policy - and after a few hours behind bars, Maggie is released.  Dr. Charles (Oliver Platt) orders an involuntary psychiatric hold on a businessman who was brought into Med after being hit by a car. Fearing the businessman is suicidal, Dr. Charles attempts to draw him out in conversation, which initially goes nowhere. Eventually, Dr. Charles is able to break through to him, and the businessman reveals his depression. We learn later that Dr. Charles has his own issues with depression after he confides to his doctor that he recently went off his meds.  Dr. Halstead (Nick Gehlfuss) and Dr. Rhodes get into a physical confrontation after Dr. Rhodes learns that Dr. Halstead plans to reach out to the woman he resuscitated against her wishes. Dr. Halstead had learned that the woman was on the placebo in her clinical drug trial - and therefore, has no hope of recovery. After the two men scuffle in an elevator, Dr. Halstead relents and chooses not to reveal the information to the patient.  Dr. Manning (Torrey DeVitto) misdiagnoses a case of shaken baby syndrome. Guilt-stricken, she apologizes to the mother for her error. Later, Manning and Goodwin organize a committee to examine all of the similar cases that have come through Med to ensure no other case of shaken baby syndrome has been misdiagnosed.
Maggie is arrested after hospital policy collides with a police case; Dr. Charles places a patient on an involuntary psychiatric hold.