His first stab at amateur sleuthing (Death in Little Tokyo, 1996) has given unemployed computer programmer Ken Tanaka his 15 minutes of fame, most of them in Japan, where he's invited to be a guest on the News Pop TV show. With the earnest friendliness of a tour guide, Ken shares what he's learning about Japanese manners, families, dining, dress, driving, and cultural assimilation, slipping in illustrative jokes as conscientiously as a preacher. Gradually, though, he realizes that the two thugs following him are interested in more than a mugging; the 17th- century sword he picked up at a garage sale is one of the keys to a treasure, and somebody (the Yakuza? a militaristic right-wing group?) has been traveling the world stealing other swords in the set and killing their owners. Lightweight vacation fare, though it does makes you worry that Ken might find himself seriously out of his depth if he fulfills his climactic vow to qualify as a private eye back in L.A.