Spoilers for the last scene of Season Three:
INTERIOR, church, decorated for a small wedding ceremony.
Priest: Do you, John Hamish Watson, take this woman, Mary Morstan, to be your lawfully-wedded wife?
John: I d-
Doors bang open at the back. Everyone gasps and turns to see what is happening.
Sherlock: John! Please wait! There is something you must know!
John: Sherlock, what the-
ROLL END CREDITS AND THEME MUSIC
BASK IN THEIR ANGUISH FOR ANOTHER 18 MONTHS