Erlendur has recently joined the police force as a young officer and immediately sinks into the darkness of Reykjavik's underworld. Working nights, he discovers the city is full of car crashes, robberies, drinkers and fighters. And sometimes an unexplained death. A homeless man Erlendur knows is found drowned. But few people care. Or when a young woman on her way home from a club vanishes. Both cases go cold. Two lost people from two different worlds. Erlendur is not an investigator, but his instincts tell him their fates are worth pursuing. How could they be linked? Inexorably, he is drawn into the blackness of the city's underbelly, where everyone is in the dark or on the run.