Gabriel Blackstone is an unscrupulous hacker and unrepentant "remote viewer" who can't resist his ex-lover's request to look into her stepson's disappearance. His investigation leads him to a rambling Victorian home that bewitches him-as do its beautiful, enigmatic owners, the Monk sisters. The pair are solar witches, obsessed with alchemy and the Art of Memory, a practice invented by the ancient Greeks. With his uneasy suspicion that one of the sisters is a killer, Gabriel sets out to determine which. But the more entangled in the case he becomes, the more deeply he is drawn into the sisters' entrancing world-losing hold of reality even as he falls into mortal danger...