Every Sherlock episode RANKED

7. The Final Problem

Now that she's out of hiding and has bombed 221b Baker Street, Sherlock's sister Eurus takes the detective and John prisoner in Sherrinford asylum, the maximum-security psychiatric facility where she's been held for years. She sets a series of tests for her brother, which sees him having to choose which of her victims live and die. Sherlock, horrified at the thought of losing another of his friends to his sister, decides to try and connect with her on an emotional level. Luckily for him, the tactic works.