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.

Follows four daring rodents - two mice, a rat and a hamster - who band together to help those in need and fight crime in the Harbor district

Doctor Nina falls in love with the charismatic architect Mark, who was imprisoned for manslaughter. Her neighbor Melanie, unlike her husband, is thrilled with Mark. But one day Melanie disappeared without a trace.