Watson and the fellows race against time to save the life of Xavier, a 21-year-old athlete with a fast-growing, seemingly incurable cancer. Meanwhile, Mycroft Holmes lets Watson know his team's work at UHOP may no longer have funding available.
A year after the passing of his friend and partner Sherlock Holmes at the hands of Moriarty, Dr. John Watson resumes his medical career as the head of a clinic dedicated to treating rare disorders. However, he soon finds that his old life is not done with him yet.