A power outage at Med puts multiple patients at risk and tests the skills of the staff and their enthusiastic med students. Natalie returns following her traumatic brain injury. Ethan and April wonder if a family is in their future.
April finds herself in a dangerous situation and Natalie gets an update on Will. Dr. Rhodes gears up for a gala honoring his hybrid O.R. and tries to convince Dr. Bekker to join him.
Dr. Charles and Dr. Halstead sink their teeth into a bloodthirsty case. Dr. Marcel and Maggie throw a traditional crawfish boil for the staff. A new relationship blossoms while another is left on rocky ground.
Will's personal issues continue to interfere with his relationship with Natalie and his life at the hospital. Dr. Bekker tries to mend things with Dr. Rhodes. Goodwin questions Maggie's life-threatening decision and Dr. Charles tries to lend a hand to the daughter of a new friend.
Dr. Halstead's world is thrown into turmoil when a former patient resurfaces. April has a secret she considers confessing to Ethan. Dr. Charles tries to maintain his focus during a difficult time.