The Return of Sherlock Holmes

While convalescing in Cornwall, a depressive Holmes investigates the apparent death from apoplexy of a local woman and the unexplained sudden dementia of her two brothers.

Holmes investigates the disappearance of a champion racehorse and the murder of its trainer on a lonely moor.

A bored Holmes eagerly accepts a case involving the disappearance of an amateur Spanish cartographer as well as his servants from his rented country lodge.

Sherlock's brother Mycroft enlists his younger sibling to locate missing patent plans that pertain to a strategically critical state-of-the-art submarine.