A young lady calls at Parker Pyne's office. Her name is Mrs. Daphne St. John and she says she is in a great deal of trouble and needs help. She produces a diamond ring that Pyne examines and declares to be worth at least two thousand pounds. Daphne tells him that she stole it from a friend of hers because she was in desperate straits. The background is that her husband is careful with money and doesn't know that she has got herself into debt. Daphne went with friends to Le Touquet and lost a great deal of money in the casino. Soon afterwards she went to stay in the country at the house of Sir Reuben Dortheimer whose wife, Naomi, was at school with Daphne. During the visit the setting of the diamond ring became loose and Naomi asked Daphne to take it to Bond Street for her to be fixed. Instead, Daphne had a paste copy made and pawned the real ring for money to pay off her debts, the paste being sent to Lady Dortheimer. Soon after, she came into some money when a cousin died and has now reclaimed the real ring. However she cannot return it as the husbands have quarrelled and the two couples are no longer on speaking terms. In addition, Naomi's character wouldn't allow forgiveness of such an act of theft if Daphne was to confess and she has heard news that Lady Dortheimer is thinking of having the stone reset. The jeweller she will send it to is bound to notice that it is a paste copy. Asked for ideas, Daphne admits that she has heard that the Dortheimers are going to be having a party on the coming Wednesday and she needs some exhibition dancers. After she has left the office, Pyne calls in Claude Luttrell and Madeleine de Sara and tells them they are going to be famous dancers...