A hiker is found dead in a remote forest that is popularly known as the "Murder Hole". Opposite the victim is a melting snowman with one eye missing. The start of a series of murders in the forest area near Freudenstadt. The handwriting is always the same: all victims show frostbite, while the left eye is covered with a black gem. The investigative team Maris Bächle and Konrad Diener has Florentin Sneelin in its sights, a reproductive doctor who lives in a romantic moated castle whose ice cellar not only stores champagne. The suspect knew the victims from a stay in a children's home many years ago. The teachers there enforced discipline and order using sometimes sadistic methods. Their wards did the same. There was a strict caste system among the children. Sneelin belonged to the lowest caste. He was a so called "Snow Child", one that his mother wanted "to foist" on his father.
The villages of Greisendorf and Neubrunn are competing for the grave of the former silent film star Gaby Gruber. But even at 114 years old, Gemany's oldest woman still has a lot of life left in her. When Greisendorf's undertaker suddenly passes away, the gardener and the garbage woman are quickly assigned to replace him.
When a poison attack is made on the racehorse Cagliostro, Lou flees the Immenhof with the horse. Together they find refuge with Cal, who lives away from civilization with his semi-wild horses. In his new home, Lou makes the horse promise that it will never have to take part in a race again. However, this is by no means the end of the threat to Cagliostro.