A man is found murdered in his Reykjavik flat. There are no obvious clues apart from a cryptic note left on the body and a photograph of a young girl's grave. Detective erlendur is forced to use all the forensic resources available to find any leads at all. Delving into the dead man's life, he discovers that forty years ago he was accused of an appalling crime. Did his past come back to haunt him? Finally, Erlendur's search leads him to Iceland's Genetic Research Centre in order to find the disturbing answers to the mystery.