sleuths with his mission for them: A large number of well-forged one-pound notes are in circulation and he wants them to track down the source. The West End seems to be the starting point in England, and some have come from across the Channel). The police are especially interested in the activities of Major Laidlaw who is involved in horse racing circles. He and his French wife seem to have a lot of money. Although it could be a coincidence, a large number of the notes have come from a gambling club used by the Laidlaws and this, together with the racing, could be an ideal way of distributing the forgeries. Another friend of the Laidlaws is Lawrence St Vincent (from A Pot of Tea above) and Marriot thinks he could introduce the Beresfords into the set. Tommy and Tuppence make their plans to catch the head of the forgers, or 'The Crackler' as Tommy calls him, named after the sound that a rustled banknote makes. The two are soon ensconced in the Laidlaw's circle of friends. As well as the Laidlaws themselves, Mrs Laidlaw's French father, M. Heroulade, is an object of suspicion. They observe how notes are passed by the Laidlaws to lay their bets. Among each wad of notes there are some forgeries. Marguerite Laidlaw is a striking woman and has a string of admirers. Among them is a visiting wealthy American called Hank Ryder who tells Tommy that she is in fear of her husband. Ryder also notices the forged notes, as his bank rejected them. The next night Tommy is at the gambling club, Mrs Laidlaw passes him small notes to exchange for one of a higher denomination. Among them are several forgeries. His suspicions are directed to M. Heroulade, but his attention is caught when he leaves the club and finds Hank Ryder drunk in the street outside. In his slurred ramblings he tells Tommy how Mrs Laidlaw took him on a treasure hunt which included a visit to Whitechapel where she "found" five hundred pounds. Tommy takes Ryder to the district and the house they visited earlier. As the row of terraced dwellings look identical, Tommy chalks a small cross at the base of the back door before they enter. Ryder thinks he hears someone coming and goes back out to investigate. Tommy goes further into the house and finds the counterfeiting gang