November 1903. Fresh from an opium den in London's East End, Sherlock Holmes relaxes with green tea and a book on beekeeping, paying no heed to Dr Watson's plea for help with a baffling case.

The corpse of a shabbily dressed young woman has been discovered in the mud flats of the Thames at low tide. Police assume she's a prostitute, but Dr Watson suspects something more and goes to his old friend Holmes, now retired and at very loose ends.

The original screenplay by Allan Cubitt re-unites an estranged Holmes and his friend Watson in a desperate bid to solve a case which threatens to overwhelm the privilege and tranquillity of Edwardian aristocratic society. Alan Cubitt previously wrote The Hound of the Baskervilles, a visceral adaptation of Sir Arthur Conan Doyle's classic as a thriller for a 21st Century audience.