Innocent souls are being stolen out of their beds in the middle of the night, and monsters stalk the blackest shadows. Seventeen year-old Harper Mellows stumbles into a world that hides in the dark corners of his slice of modern-day Australiania. It's difficult to leave the Penumbra in the first place, but when the monsters follow him back and steal what's most precious to him, Harper is thrust into a desperate race against the clock, and his time is quickly running out.