Antonia Weston has come to the sleepy market town of Amberwood in search of peace and anonymity after a shattering and all-too-public tragedy in her life. But shortly after her arrival, a series of disturbing incidents occur - incidents that eerily echo a past she is trying to forget. As she struggles to re-build her life, she becomes fascinated by the macabre history surrounding the disused watermill, Twygrist, and the now-vanished Latchkill Asylum. Memories of Latchkill still linger: memories of how, when the autumn dusk - the "spider-light" - fell, no one would dare walk past its gates. But Antonia's fascination with the linked histories of Latchkill and Twygrist has alerted someone from her own past. Someone who knows all about Twygrist's darkness. Someone prepared to use that knowledge in the most horrific way...