Magnum is to spend a week aboard a luxury cruise ship guarding an Amakua, a valuable wooden Hawaiian statuette recently purchased by Robin Masters, to be displayed on the liner while en route to the Hilo Museum. But Magnum and Higgins find that Apollo has been shot and seriously wounded after thieves attempted to steal the artifact from the Estate. Expecting the would-be robbers to try again during the cruise, Magnum secures Rick and T.C.'s additional help in guarding the artifact, but they find themselves on-board with a shipload of suspects, all potential thieves of the Amakua.

Magnum is hired by meek insurance salesman Dan Wolf to locate his father, who he has not seen for thirty years. But unawares to Magnum, the client is actually an impostor hit man who is using Magnum to help locate his victim, wealthy businessman Theo Wolf, whom he plans to kill to make a name for himself. In the hit, Magnum, too, is shot, bringing him close to death. Despite his wounds, Magnum becomes hell-bent on going after the hit man to claim revenge for the dead man's widowed wife and son, and for himself.