In 1947, long-retired and near the end of his life, Sherlock Holmes grapples with an unreliable memory and must rely on his housekeeper's son as he revisits the still-unsolved case that led to his retirement.
Adventure follows detective Enola Holmes to Malta, where her plans to tie the knot unravel when Sherlock's disappearance plunges her into a perilous case.
During WWII several murders occur at a convalescent home where Dr. Watson has volunteered his services. He summons Holmes for help and the master detective proceeds to solve the crime from a long list of suspects including the owners of the home, the staff and the patients recovering there.