A war hero, invalided home from Afghanistan, meets a strange but charismatic genius who is looking for a flatmate; it is London, 2010, and Dr Watson and Sherlock Holmes are meeting for the first time. A string of impossible suicides has Scotland Yard baffled - and only one man can help.

• Steven Moffat
• Arthur Conan Doyle
• Mark Gatiss

• Toby Jones
• Amanda Abbington
• Amanda Root