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.

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...

Magnum is hired by a beautiful Chinese antiques dealer that he's making a play for to protect a precious ancient vase, The Soul of Sung, until its buyer arrives in Hawaii to collect it. But unbeknown to him, the priceless ornament is wanted by a Tong gang from the girl's home country, and a deadly martial arts assassin who can kill in the blink of an eye is hot on the trail.

It's the Christmas season, and against his better judgment, Magnum agrees to being hired by five young schoolgirls to find their teacher, who has seemingly gone missing after falling in love. While he's working on the case, Magnum manages to convince Higgins to let the young girls stay on the Masters estate, but he's unaware that he's being deceived in a scam over a valuable painting recently purchased by Robin Masters.

Magnum returns from a case to find that Higgins' old Army commander is staying on the Masters estate, under tight security, until some I.R.A. members he helped capture are tried. Two secret intelligence agents hire Magnum to protect the brigadier and foil assassins out to kill him before the terrorists' trial, but the "need to know" basis the agents insist on operating by only serves to complicate matters for Magnum.

When a beautiful model-actress is killed by a shotgun blast in a scenario closely resembling a scene from the script of an upcoming film, it is seemingly suicide. Magnum is hired by her former producer and lover to investigate any other men that she may have been seeing before her death - a case that Magnum is reluctant to take, but, feeling guilty for not taking it before the girl was killed, agrees to.

When Saul and Lena, an aging couple who run a local shop, abruptly make plans to leave town, suspicious Magnum and Rick, who are friends with the couple, investigate - only to arrive at the pair's home to see Saul whisked away in an ambulance after suffering a heart attack. Yet when they check at the hospital, he's not there, and it becomes apparent that Saul has been kidnapped. Magnum houses Lena at Robin's Nest while looking for her missing husband, where she explains that they are Holocaust survivors who are being hunted by neo-Nazis.

Higgins volunteers Magnum's services to guard a wealthy socialite's quarantined dog after the attempted dognapping of the canine. Sir Algernon Farnsworth soon finds himself to be the most wanted dog in Hawaii when his former owner, aging gangster Victor DiGiorgio, needs to get him back.

Although Eric Tobin was reported missing in action over eight years ago, his fiancee, Laura Fraser, endowed with ESP, doesn't believe it. Arriving in Hawaii, where she occasionally has flashes involving Eric, Laura goes to work for Rick at the King Kamehameha Club as a singer. Magnum befriends her and in finding out the truth about Tobin, discovers that he was a highly trained and effective government agent working under the control of a man known only as Delta One. Magnum's search brings him into opposition with the sensitive intelligence organization, resulting in a dramatic preordained conclusion.

Magnum is hired by a Supreme Court nominee to find the woman he married on the eve of the raid on Pearl Harbor. He was a young Navy Ensign, she was a prostitute, and after their marriage they subsequently became separated in the bombings, with the Judge presuming her dead - until recently, after he started receiving blackmail threats relating to an incident 40 years ago.

Rick is organizing a surf-ski competition to be held at the King Kamehameha Club (much to the disapproval of co-committee member Higgins) when a Kahuna appears and places a "curse" on the club and all who use it. Magnum and others are skeptical, but the native locals take such curses very seriously, and it seems there may be something in it when one of the competitors suddenly collapses and dies; then, amongst other incidents, fire breaks out in the kitchen; and Rick falls ill. Magnum investigates to try and find a more logical explanation behind the events, but his inquiries aren't helped by a hounding news reporter, who sees the series of strange incidents as a chance for a big news story.

T.C. makes a late-night flight to land on a tanker, but on the journey back he is cornered and arrested by the Coast Guard for transporting drugs. Magnum and Rick are certain of their friend's innocence, but are shocked when he intends to accept the charges and refuses their help. Magnum investigates to find that T.C.'s trip to the tanker was to collect and bring home a man who once saved T.C.'s life in Vietnam, a deserter who is now supposedly a reformed drug addict, and who was calling in an old debt to be flown back into U.S. territory.

A bubbly young woman hires Magnum to find her father who, after being missing for over ten years, had sent her a postcard from Hawaii. But her father is involved in some rather shady business, and Magnum isn't the only one looking for him.

A perky woman hires Magnum to protect 'Norman', who is facing kidnap unless she pays a ransom; but the case has some unexpected turns when Magnum finds that her uncle is an old Vietnam comrade who is against him being hired, and that Norman is none other than a prized racehorse.

Having once been hired by wealthy, blind Agatha Kimball to find her missing granddaughter Amy, Magnum's services are once again called upon by his elderly friend after she has been contacted by a blackmailer claiming to have some important information about Amy. She instructs Magnum to pay the man and get rid of whatever the information about Amy is without investigating further, but when Agatha is nearly killed in a series of suspicious accidents, and when the blackmailer is shot dead during the delivery of the ransom, Magnum decides he must ignore instructions and investigate just what trouble his elderly friend and her granddaughter are in.

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 losses and end 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.

Magnum tries to impress a beautiful 'fan' of Robin's by showing her the Robin Masters estate, only to learn that she is actually a top security expert hired by Robin to test the estate's security. J. "Digger" Doyle and her boss, David, are hired by the absent Robin Masters when his life is threatened if he publishes his latest manuscript. On the chance that the tapes he uses to dictate his novels are at the estate, Higgins is kidnapped by a group seemingly led by a woman named Lisa. In a surprise twist, Magnum comes to the rescue, foiling the kidnappers and the man behind the scheme.

Magnum 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. 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.