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...

Thomas arrives in Los Angeles to deliver lawsuit papers to a small film company on behalf of Robin Masters, and during the trip befriends a stand-up comedienne. But when he finds her murdered in his hotel room, he investigates to find who is behind the killing. When he goes to deliver the subpoena to the film company, he strikes up a relationship with the attractive young attorney, and the pair work together to find the murderers... Meanwhile back in Hawaii, one of the players on T.C.'s baseball team is mixed up with some small time car thieves, who witnesses his friends being shot dead after stealing a car...

Conclusion of this feature-length / two-part story. Magnum and Cynthia became ever closer to each other as they investigate Marti's murder. Their search leads them to a drug trafficker, but their snooping around sees them almost killed. Back in Hawaii, T.C., with help from Rick and Higgins, continues to search for the missing Kenny, and get him out of the trouble he is in...