An inspector and four uniformed constables arrive one morning, unannounced, at Greystones, the imposing and remote country house of the Elderly family. Inspector Biggs brushes past the immaculate and outraged butler and demands to see John Elderly, head of the family. Behind the dark oak library door is the scene of a struggle; overturned and disarranged furniture, the telephone receiver is off the hook.... Where has the master gone? Who has cut the telephone wires and disabled the motor-cars? As more people seem to disappear, what is the inspector holding back from the assembled guests and staff of Greystones?