GO TO LONDON.
FIND THE KING'S LIBRARY.
ASK FOR ED BLACKWELL.
SHOW HIM THE KEY.
TELL NO ONE WHERE YOU ARE GOING.
THE TRUTH BEGINS IN LONDON.
THIS IS ONLY THE BEGINNING.

How it worked

Each letter in the original message was shifted one place forward in the alphabet. Decoding it meant shifting every letter one place back — a classic Caesar cipher.