Higgins sends Magnum to collect a valuable Kenzan porcelain plate, newly purchased by Robin Masters, from the airport, but the artefact, which was entrusted to the care of a Samurai warrior while in transport from Japan, has been stolen. At first, Thomas thinks the whole thing is a joke, especially when the Samurai, Tozan, claims that the plate was stolen by a ninja, but the situation is for real, and the pair team up to try and find the stolen artefact. But they must work fast, as Tozan's centuries-old culture dictates that he must commit sepuku – which means taking his own life – if the precious plate isn't retrieved...