Susanne and Christian get to know each other during a wonderful week in summer - and fall in love. This, however, leads to conflicts: up to now, Susanne has been living with Wolfgang, a biologist. This shared life was harmonious and based on mutual trust. Wolfgang is not only resolute and in full command of social situations; he has also always been the stabilizing force in the relationship. This is precisely why Susanne now feels drawn to the unsettled, unsteady and frivolous Christian, the complete opposite of the calm, well-balanced Wolfgang. And Christian, working as a shift boss on a natural gas derrick, has become more aware of his personal and social responsibilities as a result of loving Susanne.

Ten years old Ernst and his father Alfons are traveling to the family event on their bikes.

When a motorcyclist dies in an accident, lieutenant Kreutzer and his colleague Arnold receive the order to investigate the backgrounds of this mysterious case. Although the leads point to murder, head physician Dr. Nikolai, the driver of the car involved in the accident, maintains his innocence and even has an alibi. With a lot of arduous detail work, Kreutzer follows all leads and evidence. Both Nikolai’s colleagues and his son act suspiciously. Eventually, Kreutzer convicts the criminal who secretly used the physician’s car for his criminal dealings.

Dr. Roth, a respected veterinarian and head of a state-owned stud farm, had accepted papers from a man for safekeeping when he was 16 years old, toward the end of the war. Years later, they are picked up. However, this act proves to be his undoing. Before he can ask others for help, he is found dead in his car. Since espionage material is found in the immediate vicinity of the car, the police hand the case over to the State Security Service, which determines that Dr. Roth was murdered. Young Thomas, whose friend and guardian was Dr. Roth, investigates on his own to clear the man who had his complete trust. In doing so, he puts his own life in danger. Thanks to a tip from stud farm employee Renate, the security officers are able to expose the murderer, uncover his connection to the West German secret service, and clear Dr. Roth.