Chinese ventriloquist Gordon Cobb is murdered by a gang of jewel thieves. Baffled by the contradictory clues, Inspector Queen asks his son Ellery to help out.
Several days after one of his company's dams burst, ruining the life savings of several investors, a shady power company president is found stabbed to death. Ellery Queen gets to the bottom of the mystery.
The benefactor of the Stack Memorial Hospital dies after an operation. Ellery Queen investigates when it is revealed the cause of death was murder by strangulation.