Magnum has been hired by a woman to act out some of her rich, bored sister's fantasy dramas, concocted from 1930s Dashiell Hammett films. Although growing to enjoy the world of fantasy, Magnum has a hard time keeping up with the eccentric woman, and when he finds out that her husband is a wealthy, infamously jealous and bad-tempered business man, he decides to cut his loses and finish the arrangement. But he is just informing the girl that he is calling a halt to his participation, when they are attacked by real thugs, and soon after the girl is poisoned. With the woman still caught up in her world of fantasy, Magnum must thrust himself back into reality to find out just what is really going on...

Thomas is hired by Barbara Terranova, a financially broke woman who can only afford his services for one day, to find her missing fiancé Roger. But the case has several tangles in store when Magnum finds there are others searching for Roger too; And matters are complicated even further when T.C., desperate for some much-needed publicity for Island Hoppers, collars him into competing in the upcoming swim-run-bike Ironman triathlon. Fitness trainer Barbara trains him for the event in exchange for his extended help in locating her fiancé...

It's the Wild West all over again when a hot-headed young Texan hires Magnum to find his sister.

After her archaeologist father's boat is found deserted at sea in the Nehoa Channel, a young marine biologist student hires Magnum to find out what happened to him. Ancient superstitions say that the channel is ""cursed"", and local natives warn Magnum to stay away, but he is determined to get to the bottom of what happened to the missing man, and so, with aid of Rick's yaught, they go hunting for both sunken treasure, and whoever was behind the girl's father's disappearance...

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...

Magnum is hired by an attractive ""ghost writer"" who is writing a biography of eccentric millionaire Harold Farber - whom she has never met in person, communicating only via phone – when all her notes on Farber are stolen, in an obvious attempt to stop the book ever being written. As they investigate, they find themselves in the middle of a highly mysterious situation. Meanwhile, T.C. has landed himself a highly lucrative but shady piloting job delivering chemicals to a high-rise, but the building he is making the deliveries to turns out to be at the centre of the mystery...

First part of what was originally shown as a feature-length story. Nuzo, an old war comrade of T.C. and Magnum's, suddenly arrives in Hawaii, and finds T.C. to warn him that Colonel Ivan, a sadistic Russian agent who once held them captive and tortured them in a P.O.W. camp in Vietnam, is after them. At first, T.C. puts his old buddy's fears down to delayed stress, but it gradually begins to seem that there might be some truth in his claims. Meanwhile, Lt. MacReynolds resigns from the Navy, and Magnum lets him stay with him for a few days, but a fatal accident meant for Thomas - as yet unaware of Nuzo's warnings - adds ground to the fears that maybe Ivan is on the trail after all...

Conclusion of this feature-length / two-part story. As Magnum, T.C. and Nuzo plan to get to Ivan before he kills them, the Navy – inparticular Colonel Greene and Admiral Hawkes – have their own concerns in the situation and questions regarding Mac's death. But things are not as previously thought about Nuzo, and not only is T.C.'s life in great danger, but many other people's too as a result, in part of an assassination plot of a Japanese prince...

Mac's latest shady money-making scheme has landed him in trouble with the Japanese Yakuza, so he convinces Rick to buy a sailboat from him, complete with a crew of three Japanese women who barely speak a word of English. Rick is furious when Mac skips town just before the boat is impounded because Mac didn't own it in the first place, leaving Rick unable to repay Ice Pick the $20,000 he borrowed to buy the yacht, now that he can't make the money he planned by renting the boat out for charters. To get Rick's money back and keep the Yakuza and Ice Pick from doing him harm, Thomas sets out across the mainland to track down Mac.

A reluctant Magnum is hired by Ms. Jones – the clerk at the Hall of Records who often aggravates him with excessive red tape – to help her find her husband Ray. He is an expert computer programmer who has disappeared after completing work on a valuable new Artificial Intelligence formula, which could potentially be dangerous if it falls into the wrong hands...

T.C. and Magnum are fighting the demolition of T.C.'s club-house for underprivileged and troubled youths, which has been ordered to be destroyed by a greedy, obnoxious local land developer - even though he doesn't use the land. Their seemingly no-win struggle only results in a brush with the law. Meanwhile, unbeknown to them, Rick, on a trip away, wins the $1,000,000 jackpot in the Western States Lottery. Now a rich man, he meets a young woman who becomes his fiancée, but with his new wealth, he begins to neglect his responsibilities at the King Kamehameha Club, and gets mixed up with a couple of crooked poker players. Rick is so wrapped up in his whirl-wind new life that he risks loosing his job, and even more importantly, his friends, not to mention his newly acquired wealth...

A gifted deaf painter is the only eye-witness to a bank robbery in which four people were slaughtered. Carol persuades Magnum to secure the young woman on the Masters Estate and act as her body-guard when her life is endangered after identifying one of the perpetrators in a Police line-up...

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.