Someone is watching. At each abandoned crime scene there's a hidden clue: a tiny metal cog, almost invisible to the naked eye. Someone is sending Detective Sam Berger a message, someone who knows that only he will understand the cryptic trail. Someone knows.

This new series by international bestseller Arne Dahl sees Detective Sam Berger follow the trail of bodies, with a tiny cog left on each victim sending Berger specifically a cryptic message.