In the opening scenes Günther (Jürgen) is working out and boxing away at a sandsack, while his wife Hanna is in bed with her teacher colleague Albert. Guenther is a successful architect, his wife Hanna a music teacher, who uses school orchestra practice to get away from her jealous and overly possesive husband, she is seriously thinking about leaving him. When Hanna comes home from "orchestra practice" she finds, that Günther has got her a nasty gadget to protect herself from burglasrs or rapists. He has also, without asking her, cancelled her meeting with her best girlfriend in order to have time to talk to her about a subject, they have discussed a hundred times before: Günther wants Hanna to give up her job, so that they can have at last a "proper" marriage, but not children, he just wants Hanna for himself. He has even talked to the school director about the job. Hanna absolutely refuses.
On the next day, Günther wants to meet her after school and happens to see Albert and her together and knows immediately, that something is going on between the two. When Hanna comes home, there is a confrontation and she confesses to having an affair. Günther hits her, but immediately apologises and starts suggesting, how they will get through this phase together and save their marriage. He arranges for Hanna to get leave and they go to their holiday house in the mountains. The trip is not a great success and on the last day, Hanna has an accident on a hiking tour (which, I think, has not been managed by Günther, although one wouldn't put it past him). She survives, but is paralysed. Albert tries to visit her in hospital, but has to leave after a quarrel with Günther. Hanna's mother also gets involved: she is on Günther's side and tells Albert, that Hanna won't see him anymore. Günther is the most important architect in the company, that Hanna's parents have shares in and so the mother would rather keep him. Günther arranges, that Albert gets a job in another school in another city.
When Hanna gets out of hospital, Günther has her exactly, where he wanted her: in a wheelchair and completely dependent on him. He cuts her completely of from the neighbours and her friends. Hanna's mother tells her, what he has done to Albert and in the end agrees, to help Hanna to have a secret meeting with Albert. Allegedly for a good-bye. They talk again about Hanna leaving Günther.
Günther has a talent of smelling rats and finds out about the meeting. They have a fight and Günther tries to convince himself and her, that she has been talked into leaving by Albert and has to be protected for her own good. From then on, it is an open fight: She tries to get away and he tries with all means to stop her, even Albert, who comes to their house at one point, can't help her.
In the end she succeeds, because she has kept Günther in the dark about her real progress with learning to walk again. She manages to get into the garage and into the car, but the gate of the garage is shut. When Günther tries to stop her, she hits the accelerator and squashes him inn between the car and the garage door. His last words are:"Nobody will separate us!"