Karen Nichols’s slow slide to self-destruction begins a few weeks after shamus Patrick Kenzie and his fearsome sidekick Bubba Rogowski gently discourage predatory restauranteur Cody Falk from hitting on her anymore. Her fiance gets struck by a car; she loses her job and her apartment, replacing them with drinking and drugs; and she ends her final incarnation as a prostitute by taking a header off the observation deck of Boston’s Custom House. Fans of quixotic Patrick’s first four cases (Gone, Baby, Gone, 1998, etc.) will recognize Karen’s death as the signal for him to do some serious hunkering down. But every time he and Bubba, joined eventually by his estranged lover and ex-partner Angela Gennaro, get a promising lead about the plot that drove Karen to suicide, they hear the sound of doors slamming. Either Karen’s friends and family don’t know anything about the shadow that fell across her life or they’re afraid to talk about it, and the sequel shows that their fears aren’t in vain. But by the time the avengers lay down their arms, Karen’s life from childhood on will be an open book; the scoundrels who plotted against her (and there turn out to be plenty of them, coming at Patrick in dazzling waves) will be dead or defanged; and Lehane, who writes like an angel on crystal meth, will have tapped into your most primitive fantasies of vigilante justice. It’s all a fairy tale, as Patrick finally realizes. But as fairy tales go, what a scorcher!