Dr. Shaun Murphy (Freddie Highmore) continues using his prodigious medical skills at St. Bonaventure Hospital as this hit medical drama returns for Season 4. In the premiere, "Frontline, Part 1," Shaun treats a patient with an illness that not only is unpredictable but also unlike anything he or anyone else on the hospital team ever has seen before. On the home front, Lea (Paige Spara) and Shaun find their new relationship tested by the global pandemic. Antonia Thomas, Hill Harper and Richard Schiff also star.