While working on a routine divorce case, Thomas catches a brief glimpse of a woman on a passing boat that he is certain is Michelle, the girl he married during the Vietnam war seven years ago, and whom he previously believed to have been killed shortly afterwards in a bombing raid. All he has of the brisk sighting is some blurred photos he managed to take, and T.C. and Rick, whilst not completely convinced, help as he scours the local area looking for her. But there are several parties that intend to see that Thomas is unable to make contact with Michelle, and the search sees them stumbling into dangerous political territory.

In the conclusion of this feature-length / two-part story, Magnum's desperate search for Michelle faces being forced to a halt after he has been called up for active Navy duty and ordered to testify in Washington. Thomas suspects that is just a political smoke-screen to try and get him off Michelle's trail. Briefly re-united with Michelle, who is married to Vietnamese General Hue, who is involved in delicate negotiations regarding the returning remains of M.I.A.s and P.O.W.s from Vietnam. But Michelle is suspected of being a traitor agent and is in great danger...

Although he's nearly mowed down by a private plane that crashes into the estate's tidal pool, Thomas befriends the pilot, Sam Hunter, who was delivering the plane to its new owner, Mr. Sato; both men have an inkling that they've met before but can't seem to remember where or when, and Thomas has a nagging feeling that he owes Sam one, even though he can't place his finger on why; after Higgins and Thomas are shot at when they catch someone snooping around the plane, Thomas searches through the wreckage and discovers that the crash was caused by sabotage; Sam returns to Texas for his son's birthday, and attempts to reconcile with his ex-wife; after Thomas lets him know about the sabotage and that an investigation into Sato's background reveals that he's a major cocaine importer, Sam takes to the air to track down Sato and Nick, the coworker he suspects of causing the plane crash; a bit of fancy flying later, Sam forces the plane carrying Nick, Sato, and a cargo of cocaine to land right in

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.

Magnum's ex-wife Michelle leaves her five-year-old daughter Lily to be safeguarded by Thomas, as she escapes Vietnamese assassins out to kill her and her husband, General Hue. As Thomas watches over the child, he begins to wonder why Michelle has suddenly left Lily with him and if Lily is his own daughter, and once again sets about trying to track down his elusive former wife.