In this intense and transgressive German drama, the boundary between family and desire is completely shattered. Katja (Hannelore Elsner) is a woman whose outward life as a doctor's wife masks a disturbing secret. The "younger man" she is obsessively involved with in a passionate, sexual affair is actually her own son, Mark (Tobias Moretti). The film follows their hidden, incestuous relationship as they navigate the extreme danger of being discovered by Katja’s husband. As the tension rises, Katja finds herself trapped between her role as a mother and her role as a lover, leading to a psychological collapse where betrayal and blood ties collide.