Will Halstead returns to Med to help Goodwin with a secret investigation. Archer and Charles deal with twins who insist on being identical inside and out. Stevie and Dylan treat a young patient with sickle cell anemia.
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.
Goodwin assigns Med's new compliance officer to a patient with a long-hauler Covid condition. Maggie helps Will treat a patient who's been in an iron lung for 60 years. Stevie learns hard truths about her mother. Terrell returns to Med under dire circumstances.
Crockett worries he made a surgical error when a recent transplant patient comes in with complications. Carol is once again in distress. Will and Natalie must take action to right their wrong.