In the late summer of a long-ago year, a killer arrived in a small city. His name was Alton Turner Blackwood, and in the space of a few months he brutally murdered four families. His savage spree ended only when he himself was killed by the last survivor of the last family, a fourteen-year-old boy. Half a continent away and two decades later, someone is murdering families again, re-creating in detail Blackwood's crimes. Homicide detective John Calvino is certain that his own family -- his wife and three children -- will be targets in the fourth crime, just as his parents and sisters were victims on that distant night when he was fourteen and killed their slayer. As a detective, John is a man of reason who deals in cold facts. But an extraordinary experience convinces him that sometimes death is not a one-way journey, that sometimes the dead return. Here is a ghost story like no other you have read. In the Calvinos, Dean Koontz brings to life a family that might be your own, in a war for their survival against an adversary more malevolent than any he has yet created, with their own home the battleground. Of all his acclaimed novels, none exceeds What the Night Knows in power, in chilling suspense, and in sheer mesmerizing storytelling.

Twenty years after killing serial killer Alton Turner Blackwood, homicide detective John Calvino fears for the safety of his family when the Blackwood murders seem to be reoccurring. The plot contains profanity, sexual situations and violence.