As the demand for raw silk goes sky high, crooked businessman Wallace Myton corners the market with plans to drive up the price. Determined to fulfill his contracts, manufacturer Donald Kilgore imports $3 million worth of silk to Seattle and accompanies it by special train to New York. But when his secretary is found murdered, Kilgore soon discovers Myton has planted three killers on board with orders to stop the express and its passengers dead in their tracks.