Wenn alles zerbricht

The teacher Eric Klausmann disappears into the forest. There is no trace of him or his car. When his dog is found shot dead, detective Lucas and her team must assume a violent crime. They begin their investigations in the teacher's private environment. The picture of the family idyll in the Klausmann house quickly crumbles. Last year Eric had a relationship with his colleague Lisa Hübner (Liane Forestieri), the best friend of his wife Nele (Karoline Eichhorn). Since then, the Klausmanns' married life has been troubled and Klaus Hübner (Johann von Bülow), Lisa's husband, jealously watches over his wife. His 16-year-old son Kevin (Sandro Lohmann) also has serious puberty problems. Kevin threatens to be expelled from school because of his rebelliousness and also has constant arguments with his father.
As a teacher, Klausmann seemed to be well liked by the students, while father and son had not spoken to each other for a long time. Ellen and her team investigate the causes of the teacher's disappearance. Her work is hindered by Nele, who investigates on her own and withholds important research material. Such a threatening email that she finds on her husband's computer, in which not only Klausmann is massively threatened, but also an attack on the school is announced.
Could it be that the popular teacher was kidnapped by his students or even became their victim? Did Kevin kill his own father? Or is the high school graduate Konstantin (Kai Michael Müller) behind it, a student from a good family, a member of the local rifle club, who organizes target practice with Kevin in the forest in his free time?