The building contractor Borris Angersbach announced at his wife's birthday party that he wants to get more involved in politics in the future and is therefore handing over the company to his son Malte with immediate effect. Not only Angersbach's wife is outraged, but especially her son Kai. After all, he would be the rightful successor, because his mother had brought the company into the marriage, just as her husband had brought his son Malte. The next day he is found dead on the banks of the Rhine and Kai is suspected of murder. Inspector Marie Brand and her colleague Jürgen Simmel are also investigating in other directions and cannot rule out that the crime may have been an act of revenge by an employee of the company whom Malte had recently dismissed without notice. Nonetheless, Kai remains the prime suspect, because according to the investigators' research, he still had a score to settle with his stepfather. Kai was the victim of a kidnapping four years ago that was never reported to the police. Borris Angersbach had paid the ransom at the time, but accused his stepson of faking the kidnapping. This led to the final rift between the two and Kai founded his own company with his friend Daniel Weisach. When suddenly one of the registered banknotes from the ransom money from back then turns up, Marie Brand suspects a connection between the two crimes. According to her research, Angersbach had hired a detective to search for the ransom, and Malte was therefore close to exposing the kidnappers, which became his death sentence.