A car accident that occurs at the Chicago Marathon leaves a victim in critical condition and tests the mettle of Dr. Halstead, April and her fourth-year medical resident brother Noah, who must perform a difficult procedure in the field. A mother brings in her 8-year-old girl experiencing a sudden hearing loss and Dr. Manning is left to tend to the case, which takes a complicated turn. Dr. Choi deals with Olga, a woman who is malnourished, prompting him to bring in Dr. Charles to help assess the case. Meanwhile, Goodwin takes measures to get her personal life in order.

Dr. Manning tends to a young cancer patient and struggles to inform the parents of her dire condition. Elsewhere, Dr. Reese gets contacted by Danny, the troubled young man, and turns to Dr. Charles and Det. Lindsay for help in resolving a difficult situation. Goodwin and Maggie do their best to clear the logjam in the hospital and Dr. Rhodes fine-tunes his instincts after both Dr. Latham and Dr. Halstead pick up on things he doesn't. Meanwhile, a teenage science geek and her friends impress Dr. Choi and Natalie with their bio-engineering lab.

Dr. Rhodes challenges Dr. Charles and other hospital staff over the proper treatment for Robin. Dr. Manning seeks help from Det. Halstead when a sensitive case involving a young girl turns into a crime. Dr. Choi and April work together on a conflicting case. Meanwhile, Goodwin helps a friend in distress and, after eagerly awaiting, the doctors are surprised to learn who the new med resident is.

A new hotshot doctor arrives at Chicago Med causing competition for Dr. Rhodes, Dr. Halstead and Dr. Manning work together to diagnose a Syrian refugee without a medical record. When Robin is admitted back into the hospital for more complications, Dr. Reese takes a different approach to her treatment. Distracted from work because of Robin's worsening case, Dr. Charles is challenged by Goodwin and Noah hosts a graduation party that brings everyone together.