Shaun invites Aaron to stay with him while he has exterminators at his house and Lea realizes both men have a lot more in common than she realized. Meanwhile, Dr. Morgan Reznick wrestles with a big decision about her career and her personal life.

When a 3-year-old arrives at the emergency room, the team immediately recognizes he is having a stroke; Dr. Shaun Murphy's diagnosis of the underlying cause doesn't solve the problem, which has Dr. Park searching deeper.