Gary Kessler runs the Sereno Bay HOA like a small kingdom: fines for overgrown lawns, access to the front-gate cameras, and endless free time since he retired. Nobody likes him. Everybody puts up with him.

When a charming new owner moves into Building C, Gary smells trouble at once. Three buried husbands, a smile that's a little too perfect, and neighbors who, one by one, stop answering their doors. He's certain of it: she's a killer.

The trouble is that Gary is the community busybody, the man who's been crying wolf for years. The police smile politely. His neighbors roll their eyes. And while everyone laughs at the paranoid old man, the disappearances keep coming — until Gary realizes he has become the one inconvenient witness in a community where everybody watches everybody, and where no one will ever believe him.