10 Ways Sherlock Went From Great To Terrible

In The Last Vow, Mycroft states "I’m not given to outbursts of brotherly compassion. You know what happened to the other one." This seemingly throw away line which some dismissed as a joke was actually the first hint of another Holmes sibling as late as the season three finale.

The inevitable revelation that Sherlock has a sibling - and at that a sister! - is perhaps the most soap opera-y twist that Sherlock pulled, in a series that was more closely resembling a bad story line from an episode of Eastenders. As if to justify springing this twist so late and with no clues along the way we are told that Sherlock has repressed all memories of this mysterious Holmes and Mycroft has kept him in the dark to save him the heartbreak.

Sian Brooke played the part of Eurus Holmes incredibly well, and manages to hide in plain sight beautifully as the three other guises she uses to spy on John and Sherlock, but her role is largely two dimensional. Her ultimate ambition, to send her brothers and John on a series of 'games', is an incredibly unsatisfying resolution to this family conflict and one that proved the final problem for many viewers.