Belphegor, a criminal mastermind and hooded maniac, is obsessed with retrieving the lost treasure of the Medicis from its ancient burial place. Only Chantecoq, the 'king of detectives' can hope to unveil the sinister and sadistic figure that nightly haunts the Paris Louvre and its catacombs. And with that unveiling comes one of the most stunning twists. Belphegor was made into a highly successful 1960s serial for French television and it remains one of the key works of early French pulp fiction.