When a truck is robbed, one of the drivers is killed and another is seriously injured. The investigations always lead Lena Odenthal and Mario Kopper back to the shipping company, because it quickly becomes apparent that there was an informant within the company. When Lena and Kopper find out about the shipping company's payment difficulties, the perpetrator seems to have been identified. But then a second murder occurs and the two detectives have to start their investigation all over again.