Agatha Christie - The ABC Murders (Xbox One)

This is a unmissable story related achievement which unlocks when you get to room 306 in the Guesthouse, near to the end game, and solve the typewriter puzzle.

This unlocks at the end of the game, after solving the last riddle, which is assorting the burnt letter from the manor, I believe.

If you're struggling with the solution of a puzzle, you can always "use a clue" from the ingame menu (press ). This doesn't affect any achievement whatsoever and can always be used in order to progress!