Sherlock under the influence of drugs enters his own mind to solve a case from Victorian times where a bride shoots herself in the head and rises from the grave tohug her husband. If he can solve the cuddle it might lead him to how Moriarty has risen from the grave after similarly shooting himself in the head.

One mysterious case in particular baffles Scotland Yard - but Sherlock is more interested in a seemingly-trivial detail. Why is someone destroying images of the late Prime Minister Margaret Thatcher? Is there a madman on the loose? Or is there a much darker purpose at work? Something with its roots deep in Mary Watson's past.

Sherlock faces perhaps the most chilling enemy of his long career: the powerful and seemingly unassailable Culverton Smith - a man with a very dark secret indeed.

Long buried secrets finally catch up with the Baker Street duo. Someone has been playing a very long game indeed and Sherlock and John Watson face their greatest ever challenge. Is the game finally over?