1854. As the Cardiff-bound train puffs out of Paddington Station, young Hugh Kellow wraps a protective arm around his large valise. He has been entrusted with a priceless silver coffee pot, designed in the shape of a locomotive, by his elderly silversmith employer. But two of Hugh's fellow engers are taking an enormous interest in the young man and his precious cargo. When a dead body is discovered in a room at the Cardiff Railway Hotel, beside an empty valise, the great Railway Detective Robert Colbeck and his trusty sergeant Victor Leeming are called in to investigate; and face a whole host of unexpected problems.