Every year, a small group of acquaintances pay a visit to the remote, castlelike Water Mill House, home to the reclusive Fujinuma Kiichi, son of a famous artist, who has lived his life behind a rubber mask ever since a disfiguring car accident. This year, however, the visit is disrupted by an impossible disappearance, the theft of a painting and a series of baffling murders. The brilliant Kiyoshi Shimada arrives to investigate. But will he uncover the truth, and will you be able to solve the mystery before he does?