One blustery October morning in a quiet Copenhagen suburb, the police make a terrible discovery. A young woman is found brutally murdered with one of her hands missing. Above her hangs a small doll made of chestnuts.

Ambitious young detective Naia Thulin is assigned the case. Her partner, Mark Hess, is a burned-out investigator who's just been kicked out of Europol. They soon discover a mysterious piece of evidence on the chestnut man - evidence connecting it to a girl who went missing a year earlier and is presumed dead; the daughter of politician Rosa Hartung. But the man who confessed to her murder is already behind bars and the case long since closed.

Soon afterwards, a second woman is found murdered, along with another chestnut man. Thulin and Hess suspect that there's a connection between the Hartung case and the murdered women. But what is it?

Thulin and Hess are racing against the clock, because it's clear that the killer is on a mission that is far from over . . .