When Thomas's childhood friend and Naval comrade Dan Cook turns up dead, Thomas is adamant that the official cause of death, a burst bag of smuggled cocaine, is bogus, and enlists the aid of Dan's sister Alice in taking on the Navy to uncover the true nature of the top-secret assignment Dan was working on before his death.

Conclusion of the feature-length / two-part Pilot. Magnum and Alice continue in their quest to find out the truth behind Lt. Dan Cook's death, and find themselves uncovering a case of gold smuggling, and a criminal mastermind whom Magnum and Dan once knew in Vietnam. But in trying to find out what really did happen to his deceased friend, Magnum puts his own life on the line as someone tries to stop him from investigating, using any means necessary...

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...

Diane's suicide triggers memories of others that Magnum has loved who have been killed, sending him into a spiral of depression, with him fast becoming a drunken wreck. While driving through town, he catches a glimpse of a man in who looks exactly like his late friend Mac MacReynolds. Higgins, Rick and T.C. are concerned about the effect of Diane's suicide on Magnum, but Thomas is adamant that he isn't going around the bend and intends to prove to his friends and to himself that he's not going insane. But if Mac is dead, just who did Magnum see?

First in a two-part story. Tyler McKinney, an old commando acquaintance, asks Thomas, Rick and T.C. to help him rescue a buddy who is held prisoner after being captured in Chong Ker, Cambodia. The three have no reason to like or trust McKinney after he involved them in a dubious mission in Vietnam, but individually they all eventually agree to help him on the mission. They head off to Cambodia, with the unexpected accompaniment of Higgins, but the mission has dangerous consequences in store for Rick...

Conclusion of this two-part story. Magnum, Tyler and Higgins are held prisoner by the Vietnamese Major that has a reign of terror over Chong Ker. As Rick lays recovering from his wounds, T.C. works with a local he's befriended trying to repair an old helicopter for their escape, but it becomes apparent that Tyler has been deceitful about the true nature of the mission...

When Rick's boat returns from a cruise deserted, Magnum searches for the answers to what has happened to his friend and the passengers on-board, who are all presumed dead. His hunt is somewhat hampered by the separate investigation of a law officer who models himself on John Wayne, but as they both try to get to the bottom of the strange disappearance of the boat's passengers, they stumble upon a plot involving mobsters and two million dollars in counterfeit money...

At the 14th Annual Convention of Private Investigators, Magnum is to receive the 'Local P.I. of the Year' award, but the event is brought to a halt when Jean Claude Fornier, the famous French Detective, suddenly drops dead while giving a speech, after being poisoned. Magnum is helped - or rather, hindered - by several fellow crime-busting acquaintances as he seeks the murderer, and becomes entangled with a gang of drug smugglers, that the Inspector was hunting before he was killed...