London is in the grip of a stifling heatwave. The city has slowed to a claustrophobic shuffle. Heroin-addicted investigator Catherine Berlin suffers while working the lowest of investigations: matrimonial. The city's junkies are in the grip of a drought of a different kind. Sonja Kvist a strung-out ghost from Berlin's past, turns up on her doorstep. Sonja daughter is missing. An unpaid debt leaves Berlin no choice but to take the case of the missing ten-year-old. Berlin is back. And 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.