Simon Lee has called together his many offspring for the Christmas season - with the express purpose of tormenting them for his own amusement It is hardly surprising then that he is found murdered in hideous circumstances and in a locked room Hercule Poirot, staying with friends in the district, is asked by his old friend Colonel Johnson, Chief Constable of Middleshire, to take on the case, and finds he needs all his mastery to solve the audacious crime