Watson and the fellow spring back into action when Mary's mother accidentally poisons herself while suffering from a rare form of dementia that is progressing with impossible speed. Sherlock Holmes resurfaces after being presumed dead.

Having been presumed dead, Watson is shocked to discover Sherlock Holmes in his apartment, and recounts a recent case involving a microbiology team being afflicted with a "zombie virus".

A newly reinstated Ingrid helps the team treat a 30-year old patient who appears to be only 10.

Watson and team treat 4 patients with suspected flesh-eating bacteria after tornado. Shinwell seeks purpose in nursing school while Adam's wedding to Lauren faces obstacles.

While visiting another hospital, Watson becomes convinced that a man is suffering from locked-in syndrome and has been mistaken for a coma patient for over a decade; Sherlock is back in town and is staying with Watson.

The team rush to save a young athlete with an apparently untreatable tumour. Further troubles arise when Mycroft Holmes throws the clinic's future into doubt.

Watson's father, Hamish, visits UHOP to introduce Watson and the fellows to his protégé, Annabelle, a saxophone prodigy with musically induced blackouts.

Watson and the fellows are taken hostage by a man with a bomb strapped to his chest who is desperate to find a cure for his 9-year-old daughter's illness.

Watson and the fellows help Laila's son Micah, who was injured in a car accident while pursuing his crush.

Hobie, Watson's bio-hacker friend, brings his girlfriend to Holmes Clinic after a failed gene-editing experiment. Watson becomes concerned for Sherlock.

Watson and his team rush to rescue a man and his pregnant wife trapped in a dangerous sinkhole while Ingrid faces uncertainty about her therapy group's future.

A patient with a tragic past arrives with a strange neurological condition, and Adam struggles with his impending fatherhood.

Watson and his team battle to save a woman experiencing repeated heart stoppages.

Watson is sued by a longtime patient after enduring a lifetime of painful surgeries.

The team races to enact a life-saving kidney operation. Meanwhile, Sherlock resurfaces to investigate an unsolved case.

Watson examines a case with a mentally unstable mother whose delusions reflect his own recently discovered hallucinations.

In the wake of the car accident, Watson and Laila lie injured and awaiting rescue as the team races to find them before it's too late. Meanwhile, Watson's mind plays out a modern-day investigation of a case that has long haunted him.

Lauren's C-section goes wrong when her OB-GYN passes out. Watson and Mary's search for a famed surgeon is interrupted by a severe storm.

A seemingly random murder outside of UHOP sets the stage for the arrival of someone from Watson and Sherlock's past.