Treachery becomes a habit.
London is in the grip of a stifling heatwave. The parched city has slowed to a claustrophobic shuffle and there's no end in sight. Heroin-addicted investigator Catherine Berlin suffers while working the nadir of investigations: matrimonial.
The city's junkies are in the grip of a drought of a different kind. A strung-out ghost from Berlin's past turns up on her doorstep: Sonja Kvist's daughter is missing. Despite Berlin's reluctance, Sonja reminds her of an old debt and Berlin agrees to search for the ten year old.
Berlin is back. Soon the hunter becomes the hunted – corrupt detectives are on Berlin's tail chasing drugs she doesn't have, a young girl is murdered and the matrimonial case unravels. The temperature keeps rising.