Dr. John Watson resumes his medical career as the head of a clinic dedicated to treating rare disorders six months after the death of his friend and partner, Sherlock Holmes, at the hands of Moriarty.
A man with a bullet in his brain claims to be a Scottish soldier, hiding dark secrets. Watson investigates while searching for Mary's new lover and helping Ingrid overcome her lying tell.
Watson and the fellows treat a comic who collapsed at an open mic night; the team becomes concerned when Watson himself collapses and suffers another traumatic brain injury.
Watson risks his career to treat a sickle cell patient with an unorthodox surgery. Meanwhile, Ingrid attempts to get her sister admitted to her spinal project.
Stephens musters the courage to ask Watson to help him when his camgirl suddenly collapses during a video call; the team must act quickly to locate her before it's too late; Watson grapples with guilt over Sherlock's death.
While Watson and the team help a woman whose memory resets every three minutes, Watson struggles with auditory hallucinations and questions whether someone is behind his current decline; Moriarty plots his next move.
Watson runs into an old friend of Sherlock Holmes when her son Angus is admitted to UHOP for temporary paralysis; the fellows help Watson after he grows fond of Angus, pursuing various leads to find a cure to his illness.
Ingrid tests her experimental paralysis treatment on her sister Gigi. After she starts exhibiting side effects, the team gets involved. Meanwhile, Mary and John bond following a tragedy.
The clinic's latest patient, who is under treatment for Alien Hand Syndrome, comes under suspicion of fatally pushing his brother in front of a bus. Watson must determine if he is guilty or innocent.
Watson confronts a past trauma from his days in the military when an Army friend's wife reaches out for help, concerned her husband is having a psychotic break. Meanwhile, Moriarty has one final task for Shinwell.
