Carol persuades Magnum to do some work for her, gathering additional evidence for the big murder case of a man accused of killing his wife that is due to come up in court in a couple of days. The only witness of the woman's death is her young daughter, but Thomas faces a crisis of conscience over just what to and what not to present as evidence in the court-room that could ensure the conviction of the violent accused killer... Meanwhile, Higgins, tired of Magnum's slackness around the Estate, has taken use of the Ferrari away from him, so Thomas must find a new vehicle to get around in...

At request of Robin Masters, Thomas begrudgingly is to provide protection for a political candidate whom he has reason to dislike. He is also waiting for a female client, but in her place arrives a young Vietnamese boy, Tran Quoc Jones, who wants to hire Magnum to find his long lost father, a pilot in the Vietnam war. Tran cannot go to the authorities for help as he is an illegal immigrant and would face deportation, and as Thomas does his best to trace the boy's father, he and his friends, especially T.C., become attached to the boy. But Magnum learns that the woman who was originally to have hired him was found murdered - and the politician, the dead woman and the young Vietnamese boy all tie in to the same case...

Magnum and Higgins travel to London, England to oversee the establishment of Robin Master's new castle, Robin's Keep, in time for a large banquet. While Higgins is busy training Ian MacKerras for the running of the castle, Thomas takes the opportunity to visit Geoffrey St. Clare, an old friend from Vietnam, but upon arrival, Geoffrey's wife Penelope informs him that Geoffrey has been killed, after being run down in a hit-and-run incident with a black Jaguar. But there is mystery surrounding the death - Geoffrey was supposed to be in France, and the circumstances suggest that, far from being an accident, the death was deliberate murder.The events of Geoffrey's killing seem to be echoing a disturbing, bizarre dream that Magnum had on the journey to England...

Conclusion of this feature-length / two-part story. As Thomas and Penelope investigate the mystery surrounding Geoffrey's death, they become close to each other, and Thomas with this and with flashbacks to his haunting dream that seems to have predicted Geoffrey's death, he feels as though he's almost stepped into Geoffrey's life. The pair uncover that Geoffrey was once part of a powerful group of assassins, and seems to have been killed to stop him from having chance to expose the group. Meanwhile, Thomas learns that Higgins is reluctant to use the stay in England as an opportunity to visit his father, whom he has not seen in forty years after a falling out...

A supposed wealthy teenage ranch owner hires Magnum for $100,000 to stop a dangerous group of cattle rustlers on Hawaii's big island, that will soon force his ranch into bankruptcy if many more cattle are taken. But Magnum finds that his employer isn't quite all he makes out to be and will go to any extent to protect his cattle, and the neighbouring ranch owner implicated of being behind the cattle theft is a business partner of Robin Masters'...

As he and T.C. deep sea scuba-dive, Thomas sees a young boy who appears out of nowhere with no breathing apparatus and signals him to follow. Low on air, Thomas is unable to follow him, and later faces the skepticism of T.C., Higgins and Rick about his vision. An adamant Thomas, determined to prove that he's right, learns that his vision matches the description of a young boy, Keli'i Parker, killed five years earlier in an explosion at sea. The boy's mother has always blamed herself for his death, and as Thomas learns more about Keli'i, he begins to believe that his vision of the boy was destiny reaching out to lead him to the cause of the fatal accident.

After being expelled from a number of expensive schools, R.J., Robin's rich, careless, teenage nephew, arrives at the estate to be reformed and educated by Higgins. R.J., however, has other ideas and decides to impersonate Thomas after being impressed by his adventures. Hired by a woman to find the only witness to her husband's murder, R.J. manages to get Thomas and everyone else involved in the case targeted for death by the men who killed the woman's husband.

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...

1940s San Francisco: Private Investigator Thomas S. Magnum investigates the murder of newspaper tycoon William Maxfield. The case involves characters that strangely bear a strong resemblance to (modern day) Magnum, T.C., Higgins and Rick...

Thomas is in Chinatown with Rick and T.C. celebrating his upcoming fortieth birthday, but he has little to celebrate when he loses his lucky $2 bill that his Grandpa gave him as a boy. While looking for it, he meets a beautiful woman who may cost him not just his lucky bill, but his heart -- and possibly his life.

Magnum's P.I. license has expired. He is tied up in red tape trying to renew it when his aunt -- best-selling, Pulitzer prize-winning playwright Phoebe Sullivan -- pays him an unexpected visit. She just finished authoring a new play and is convinced someone is trying to kill her for it. Is someone really after Aunt Phoebe, or is her mind playing tricks on her?

Magnum is hired by an attractive woman to find the missing will of her late father, who was recently killed in a suspicious boating accident - which she suspects her brother of being behind, in order to steal the will. Working on the case, Thomas finds that former client Susan Johnson – whom he was once locked in a bank vault with – is now a fellow Private Investigator, and is working on the same case – for the brother, who suspects his sister as responsible for their father's death. The two P.I.s are soon locked in a battle of wills as they both race to solve the investigation first, but the pair are forced to put their rather love-hate relationship to one side and team up to solve the case of sibling rivalry...

Magnum prepares for the trial of Quang Ki, who attempted to kill both him and his family. But when the case is suddenly, unexpectedly acquitted, angered Thomas suspects some other hand is behind Ki's release. It becomes evident that his arch-nemesis will stop at nothing to destroy Thomas and his family, when he receives a video-tape containing terrible information about the fate of his former wife and young daughter. As Thomas plans his revenge against Ki, he is thrust into a quagmire of intrigue endangering a sensitive P.O.W. prisoner exchange programme...