Mr. Dench left his house on a wet September night to post a letter at a nearby pillar-box - and disappeared. A fortnight later his dead body was found in a tunnel a few miles away. He had been brutally murdered. Called in to investigate, Superintendent Robert Budd soon realizes that Dench hadn't planned to disappear. But it's not until he finds the secret of the fireman's helmet, the poetic pickpocket, and the Witches' Moon that he discovers why Mr. Dench - and several other people - have been murdered...