Nine keys. Nine bodies. One pattern only two investigators can see. When a locksmith's tool turns up beside a corpse with no forced entry and no stolen goods, detectives write it off as a fluke. Then it happens again. And again. Each victim is left with an antique key that fits no lock anyone can find — until the ninth appears, and the truth beneath the city finally surfaces. A partnership forged under pressure must untangle a killer's private mythology before the last door opens for good.