The manor's rumored one-hundredth door may conceal secrets hidden as deep as the estate's bookshelves extend high . . . but the haunted past has a way of ensnaring curious souls.

In 1888, Minnie Tipton finds herself beset by the dark superstitions that envelop the Pennsylvania mansion her father bought. Convinced the vengeful spirit of a Civil War captain haunts the house and worried by her father's rapidly worsening illness, Minnie delves into the home's fraught past in an effort to bring him peace. Yet the lingering impact of the war and the gruesome tale of murder she uncovers only foster more fear and threaten to unravel Minnie's own sanity.

In the present day, Triss Bellamy eagerly steps into the role of bookshop manager in the mansion-turned-museum boasting ninety-nine doors. But Triss's dream job turns into a nightmare when havoc breaks loose with the arrival of her brother's team of self-proclaimed paranormal investigators. Their determination to find a rumored one-hundredth door--a dangerous portal to the madness long said to plague the mansion--results in calamity, leaving Triss no choice but to hunt down the truth or watch her brother slip forever beyond her reach.