Winter, 1962. An avalanche seals the Hôtel Belmont-Glace, a quiet accountant is murdered in his bed, and the killer is one of the 42,118 guests written into the register at the back of the book.
Twenty checkable clues narrow the field to a single name. This is the sealed Final Dossier that tells you who she really was, what she had been hiding for thirty years, and the detail in Edmund Vance’s margin that nobody in 1962 understood.
Solve it first. The truth will keep — it has kept for thirty years.
Spoilers, obviously. Open it only once a single name is left standing on your Tally Ladder.