Dr. Manning rushes to save a young boy with a life-threatening case of the flu; April suspects Dr. Choi's sister stole opioid pain killers; Dr. Rhodes and Dr. Bekker disagree over the best treatment for a cardiac patient who is 21 weeks pregnant.

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.

After a major accident at O'Hare, the E.D. is concerned one of their own is in mortal danger. Will's proposal for a safe injection site goes to the board for consideration. Natalie and Goodwin become concerned for Gwen.

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.