It is the eve of Emerald Torrington's twentieth birthday and the family has assembled at Sterne, the once grand, now crumbling, family seat. The cake is iced, the wine decanted, the house gleams invitingly.
But before the first dish can be served, a mysterious group of strangers arrives at the door. Victims of a local train accident they are seeking shelter at the house.
The Torringtons welcome them in but there is something unsettling about the group and, as night falls and a storm rages outside, the family begins to wonder if something more malevolent than stranded travellers is in their home...