Charlie Chan of the Honolulu Police is in Lake Tahoe when the glamorous opera singer Ellen Landini is shot dead at the party he's attending. Sheriff Don Holt is relieved to have Chan's assistance. There are four suspects - Landini's widower and her former husbands - and a paucity of clues. However, Chan finds clues from a galley proof of Landini's forthcoming autobiography. And it appears that Ah Sing, an elderly, Chinese houseboy and 'Keeper of the Keys', is an important piece of the puzzle, although he is fiercely traditional and uncooperative. However, Chan's cultural knowledge works to his advantage in solving the case.