The Chestnut Man is set in the quiet suburb of Copenhagen, where the police make a terrible discovery one blustery October morning. A young woman is found brutally murdered in a playground and one of her hands is missing. Above her hangs a small man made of chestnuts. The ambitious young detective Naia Thulin is assigned to the case, along with her new partner, Mark Hess. 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 was presumed dead - the daughter of politician Rosa Hartung.