Someone in the House

When Anne receives an invitation from her friend Kevin to spend the summer at Grayhaven, his family's newly acquired medieval manor in Pennsylvania, she eagerly agrees, hoping to finalize their book on contemporary literature. However, as the weeks pass, Anne becomes increasingly aware of an unsettling atmosphere within the house, and despite their best efforts, she and Kevin find they haven't written a single sentence. What secrets lie within Grayhaven that keeps them from focusing on their work?