Two years on from reports of his Reichenbach Fall demise, Sherlock resurfaces as London comes under threat of a huge terrorist attack. John, though, has mixed feelings – he's delighted by the return of his best friend, but harbours worries that the consulting detective's reappearance will have an adverse affect on his settled domestic life, in particular his romance with Mary Morstan.

• Steven Moffat
• Arthur Conan Doyle
• Mark Gatiss

• Toby Jones
• Amanda Abbington
• Amanda Root