A young Swedish man is found murdered in a simple hotel room in south London. Shortly afterwards, a similar murder is committed in Gothenburg (Sweden). The crimes seems to be related.

DC Erik Winter's holiday is cut short at four o'clock on a hot summer morning. An unidentified young woman is found murdered outside Gothenburg. No one seems to miss her.

DC Erik Winter is on the Spanish coast, where his father is seriously ill. At the same time, a grisly double murder is committed in central Gothenburg. Winter and his co-workers are faced with a seemingly hopeless riddle whose answers seem increasingly complicated the closer they get to the solution. Winter begins to suspect that he himself has been assigned a part in the killer's diabolical plan.