It's 1923 and at Thistlecrook House, a forbidding home on the Scottish border, the roaring twenties seem not to have arrived. But Simon Christie has - a young man who can't believe his luck when he gets a job cataloguing the infamous art collection of the Mordrake family. Yet from the moment he gets off the train at the deserted village station he can't shift a headache and a sense that there's more to the House and its gruesome selection of pictures.

Simon's host is glad of his company, but he gets the feeling the house is not so welcoming. As his questions about the Mordrakes grow, he finds answers in surprising places. But someone is not pleased that old secrets are stirring.

As night falls each evening, and a growing sense of unease roils in the shifting shadows around him, Simon must decide what he can trust and ask if he can believe what he sees in the dusk or if his mind is poisoned by what has happened before in this place between lands, between light and dark.