During their thirty years of marriage, Rose Redfern has confided everything (well, nearly everything) to Michael, and is certain that he would never hide anything from her. That's why it's such a shock when, shortly before Rose and Michael are set to take a romantic trip to Venice, she receives strong evidence that he's having an affair with a woman their daughters' age. Rose feels emotionally unmoored, and her sense of betrayal swiftly turns vengeful. She stumbles across a stash of powerful barbiturates, previously used to medicate an epileptic dog, and wonders if she might not find a new use for them…But is Michael truly unfaithful to Rose, or is someone seeking to destroy the Redferns' lives - and can that person be stopped before it's too late? Night Visitor is a frighteningly plausible scenario of how secrets and jealousy can tear people apart.