Dr. Murphy treats a patient who has an illness that is not only unpredictable in nature, but also unlike anything he or the team has seen before. Dr. Claire Brown continues to work through her grief, still reeling from Dr. Neil Melendez's death.

Dr. Shaun Murphy and the team try to get a better understanding of COVID-19; Claire looks for a way to grieve Melendez's death through her patients; Dr. Alex Park and Mia discuss their future together.

With several candidates vying for residency at St. Bonaventure, Chief of Surgery Dr. Audrey Lim tasks Dr. Shaun Murphy, Dr. Claire Browne and Dr. Alex Park with mentoring the top first-year resident contenders. As their mentees shadow them for the day, Shaun and Park meet with Andrews to discuss a difficult surgery scheduled for a minor. Later, Shaun inadvertently insults Lea while discussing the pros and cons of the controversial surgery. And elsewhere, Dr. Morgan Reznick seeks out Claire and Lim's help on a consult.

Morgan and Shaun's pregnant patient with twins is having pain and they are forced to grapple with a decision no-one wants to make. Shaun asks Lea to move back in despite her reservations.

Shaun questions his decision to give the new residents autonomy when an intern's misdiagnosis has dire consequences. A patient has a ruptured cyst affecting key functions of her brain. Morgan and Park bond over failed relationships.

As Chief of Surgery Dr. Audrey Lim struggles to cope with the residual emotional trauma of COVID-19, she encounters a young war veteran fighting debilitating PTSD. After discussing his case with the team, Dr. Claire Browne suggests a radical treatment to help him. Meanwhile, still reeling from the recent loss of his mentee's patient, Dr. Shaun Murphy declares he doesn't want to teach the new residents anymore. And elsewhere, an eccentric patient keeps the team entertained.

Dr. Morgan Reznik discovers her patient's wealth and obsession with extending his life is a dangerous mix that could end up costing more than he can afford.

The team treats a teenage gymnast who experiences complications from her intensive training; Shaun meets Lea's parents for the first time.

Lim is challenged by the unique circumstances surrounding a pregnant patient with an aggressive tumor. Elsewhere, after misdiagnosing a patient, Claire makes a disconcerting discovery about certain practices at the hospital.

When the hospital is hit with a cyberattack threatening to shut down life-saving machines, Lea rises to the challenge and looks to outsmart the hackers to prove herself. Meanwhile, the team treats an inspirational cancer survivor-turned-successful-philanthropist who harbors a dark secret.

After bringing in an incredibly unique and complicated spinal surgery, Dr. Aaron Glassman challenges the residents for an opportunity to join him in the operating room. Meanwhile, Shaun and Morgan disagree on how to treat a comatose patient with a cancerous tumor.

When a renowned surgeon comes to St. Bonaventure for treatment, the team's enthusiasm is quickly overshadowed by the doctor's behavior. After studying his case, Dr. Shaun Murphy sees a pattern he recognizes. Meanwhile, Shaun and Lea are forced to make a life-changing decision that will alter the course of their relationship.

Claire is blindsided when her absentee father shows up at her door. Meanwhile, Shaun feels disconnected from Lea, causing tension in their relationship.

After finding out the gender of their unborn child, Lea's enthusiasm prompts Shaun to make an effort to be a more supportive partner. Meanwhile, the team treats a navy pilot whose previous doctor's misdiagnosis compromises her chances at a full recovery.

After a political protest turns unhappy, the team races to save two young gunshot victims.