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.