The setting: a faded, lonely guesthouse on the Essex coast. Outside, it's dark, and very foggy. Inside there's no phone or internet reception, no connection with the outside world.
Enter a promising young academic en route from the USA to an important convention in Holland. With his plane grounded by fog at Stanstead, he has been booked in for the night at the guesthouse. Discombobulated and jetlagged, he falls in with a family who appear to be celebrating an anniversary of some sort.
But this is no ordinary celebration.
Presiding over the evening is an ancient and malign matriarch in a wheel-chair. With her is a medium charged with calling up the restless spirit of the old woman's dead son. As evening becomes night, it transpires that the old woman exercises a ruthless control over her family who are caught up in an insidious web of secrets and lies.
It isn't long before our young academic finds that he too is implicated in the unfolding events - and that it's not the dead he should be worrying about, but the living ...