Martin Beck gets a phone call from his German colleague, Hans Sperling, who is in Stockholm to buy a painting at auction. Sperling has found a dead woman in his hotel, and needs Martin's help. The murder investigation leads them into a dark world of art fraud.

A paparazzi photographer is found dead, his apartment ransacked. When Beck's superior Margareta Oberg goes through the evidence, she reacts very strongly to two of the images left behind, going so far as to hide them from the team. Who was in the photographs, and was the motive for the murder revenge, blackmail or something even more sinister?