A strange voice from inside the woods, repeating a child’s counting rhyme. A body discovered in the water. Thirty years later, a woman begins receiving a string of anonymous text messages, repeating that same rhyme. Then she disappears. On Valentine’s Day, detectives Naia Thulin and Mark Hess are searching to find the missing woman. But when they uncover links to a decades-old cold case, their investigation takes a terrifying turn. A violent killer is on the loose. Can Hess and Thulin catch them before they strike again?

A psychopath is terrorizing Copenhagen. His calling card is a “chestnut man” --- a handmade doll made of matchsticks and two chestnuts --- which he leaves at each bloody crime scene. Examining the dolls, forensics makes a shocking discovery --- a fingerprint belonging to a young girl, a government minister’s daughter who had been kidnapped and murdered a year ago. A tragic coincidence, or something more twisted? To save innocent lives, a pair of detectives must put aside their differences to piece together the Chestnut Man’s gruesome clues. Because it’s clear that the madman is on a mission that is far from over. And no one is safe.