Heroin-addicted investigator Catherine Berlin hides her scars from prying eyes while working the worst of all cases: matrimonial. Meanwhile, the junkies suffer from a drought of a different kind. London sweats in the height of summer. The parched city has slowed to a claustrophobic shuffle and there's no end in sight. A strung-out ghost from Berlin's past turns up on her doorstep with a desperate plea for help: her 10-year-old daughter is missing. Reminded of a debt owed, Berlin agrees to help, but the search becomes far more deadly than she could ever imagine, drawing her deep into an underworld of corrupt detectives, ruthless drug dealers, and a child killer.