Robin's friend and aspiring writer Betty comes to the estate for a quiet place to overcome her case of writer's block as she works on her mystery adventure novel. In short order, she convinces Higgins to hand over the keys to the Ferrari and to relocate Thomas to the main house while she works in the guest house, much to Thomas's extreme displeasure. After Thomas is forced by a lack of transportation to let her observe his investigation of a hit-and-run insurance case, she begins to churn out a story inspired by Thomas's case, featuring Thomas as dashing international investigator Sebastian Sabre, Higgins as his faithful servant Boris, T.C. as his pilot Winston, Rick as club owner Swift, and herself as Sabre's glamorous girlfriend Collette. Her wild imagination unwittingly breaks open Thomas's investigation and plunges them both into danger.

Photographer Sally Faraday, looking to hire Magnum, meets him in undesirable circumstances when she prangs the front of the Ferrari while being pursued in a car chase by two men, an incident which also leaves Agatha with a broken ankle. Sally wants Thomas' help when it seems that she is being followed since returning from France with some photographs for a new book, in which she seems to have caught something on film that someone has reason to not want to ever be published...