 Billie Bronson (Louise Henry) secretes a package in the trunk of Charlie Chan (Warner Oland) aboard a New York-bound transatlantic liner. Chan and his number one son, Lee (Keye Luke) are met at the pier by Inspector Nelson (Harold Huber) and two rival reporters, Joan Wendall (Joan Marsh) and Speed Patton (Donald Woods). Bille, having left the country hurriedly a year ago when sought as a material witness in a political scandal, has returned to "blow the lid off the town." She follows the Chans to their hotel and attempts to regain her package from the trunk, only to be interrupted by Lee. She then goes to the "Hottentot Club", where "candid-camera night" is in full progress, followed by Lee. Already present are Joan and Speed. Billie is mysteriously murdered and Charlie is summoned from a police banquet in his hornor. Present in the room with the body are club manager Johnny Burke (Douglas Fowley) ; club dancer and Burke s girl-friend Marie Collins (Joan Woodbury) and the two reporters. While seeking a motive for the murder, a second killing is discovered in Charlie s hotel room, the package is missing from Charlie s trunk and it is realized that it must have contained her diary. Charlie neatly puts together a few scattered clues and names.......as the killer.