In The Trick That Failed, Diana Fulvers was the daughter of an oil millionaire. Flight Lieutenant Rosten, having absconded with £12,000 of his R.A.F. station payroll, decided to return to Britain from France to fetch her. Diana, in her late teens, had intended to elope with him and marry him in Paris. Rosten planned to take her away in a Jodel D11 which he brought in from France and put down in the New Forest. Fortunately for Diana, Ginger spotted Rosten's Jodel coming in from the Channel coast. He and Biggles were on hand to stop Rosten just as the couple was getting into their escape aircraft. Rosten was arrested and Diana put wise about Rosten's marital postion: he already had a wife. A week after Rosten's trial, Diana and her father Otto Fulvers visited Biggles to thank him for saving Diana from what could have been tragic consequences.