Billie Bronson secretes a package in the trunk of Charlie Chan aboard a New York-bound transatlantic liner. Chan and his number one son, Lee are met at the pier by Inspector Nelson and two rival reporters, Joan Wendall and Speed Patton. 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 honor. Present in the room with the body are club manager Johnny Burke; club dancer and Burke's girl-friend Marie Collins 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.