Dr. Manning and Dr. Halstead become skeptical of a patient's injuries when the victim of a car accident is brought into the hospital. Ethan and April have a difficult time understanding Emily's attachment to her boyfriend despite recent developments. Will and Natalie brace for their joint bachelor/bachelorette party.

Will and Natalie prepare for their big day, but an unsuspecting Will soon finds himself sidetracked. Dr. Charles disagrees with Goodwin on how to best handle a patient's treatment while Dr. Choi and April are on their own when a pregnant woman delivers. Dr. Rhodes finds himself operating on a patient that is of great importance to Det. Halstead.

Halstead hides the theft of his gun from a suspicious Manning. Tensions are still high between Connor and Bekker, who take a risk operating on an HIV-positive patient. Hank breaks down when he sees a patient from his past.

Dr. Charles and April team up to take on a mysterious patient in the ED. Dr. Halstead is forced to make a life-or-death decision for one of his trial patients. Dr. Marcel is confronted by his past when a former acquaintance is brought into the ED.

Will runs into trouble when one of his trial patients falls ill. His own stress and symptoms have Ethan struggling to get through the day.

Crockett deals with a patient who ends up having more in common with him than he thinks. Will and Ethan clash over a pregnant patient with an irregular heartbeat.

An auto accident sends Goodwin into a spiral as she tries to help a young boy and his mother. Natalie's secretive behavior begins to draw the attention of Dr. Marcel and Dr. Halstead.

Dylan's loyalty to Med and the police department is challenged when an old family friend and veteran cop exhibits concerning behavior. The annual random drug testing puts a doctor’s career in jeopardy. Ethan tries a risky old-school method on a patient. Will helps Stevie search for her mother.

The outcome of Will's investigation weighs heavily on his mind as he works with Dylan to save a 4-month-old patient. Stevie and Vanessa both struggle to keep their secrets. Crockett and Blake work with Abrams to save a patient in need of a liver transplant.

Will and Stevie get stuck in the middle of a marital face-off. Dr. Blake's entire surgical team mysteriously collapses during a liver transplant. Charles encourages Ethan to reconcile with his father.

A woman from Archer's past returns and threatens his transplant surgery. Marcel clashes with Med's new eager first-year resident. Charles works to repair his relationship with Ripley.

Goodwin recruits Charles to evaluate her ex-husband's memory. Archer treats one of Sean's peers from the rehab center. Asher treats a woman from a rural clinic whose miscarriage was improperly treated.

Maggie empathizes with a patient whose mother is afraid to consent to her son's risky surgery. Ripley treats someone from his past. Ahmad questions her instincts.

Archer, Asher and Charles encounter an expecting father who claims he's telepathic and receiving messages from his yet-to-be born son. Ahmad works to thaw out a frozen criminal.

Ripley and Charles treat a high-risk prisoner who may have dementia. Archer and Sean clash when a resident from Margo's facility lands in the E.D. Marcel receives shocking news.