Mr Holmes is a new twist on the world’s most famous detective. In 1947, an aging Sherlock Holmes returns from a journey to Japan, after searching for a rare plant with powerful restorative properties. In Japan he witnessed the devastation of nuclear warfare. Back home, in his remote seaside farmhouse, he has the company of his housekeeper and her young son Roger, while he revisits the circumstances of the unsolved case that forced him into retirement, relying increasingly on Roger’s help.