Jason Thomas Brown

During a handover to the head of counter-terrorism of MI5, Harry Pearce, a terrorist escapes custody. When Harry disappears soon after, his protégé is tasked with finding out what happened as an impending attack on London looms, and eventually uncovers a deadly conspiracy.

John and Lestrade try to move on with their lives after Sherlock's apparent death. However, Anderson believes he is still alive.

Mark, a street photographer, becomes obsessed with a woman he photographed who he has never met.