'The horror on the train, great though it may turn out to be, will not compare with the horror that exists here, in this house.' On Christmas Eve, heavy snowfall brings a train to a halt near the village of Hemmersby. Several passengers take shelter in a deserted country house, where the fire has been lit and the table laid for tea - but no one is at home. Trapped together for Christmas, the passengers are seeking to unravel the secrets of the empty house when a murderer strikes in their midst.