The investigations for Lena Odenthal and Mario Kopper begin on the banks of the Rhine, because that's where the water police recovered Konrad Hanke's body. He was beaten and then thrown into the water. Hanke was originally a motor racing engineer, but has been working in his sister-in-law Silke Grimm's shipyard since the accidental death of his wife... Lena and Kopper think it's possible that his death is related to his previous job, because on the evening of his death Hanke met a racing team owner - and Gabi Stein, the racing driver who was involved in Hanke's wife's fatal accident a year earlier. Daniel, Hanke's 19-year-old son, threw a tantrum at the meeting because he still blames Gabi Stein for his mother's death.
Disturbed and easily excitable as he is, Daniel is certainly one of the suspects. But Lena and Kopper are also interested in the interest racing team owner Hamacher had in Konrad Hanke. When Hanke's computer is stolen, it reinforces her suspicion that Hanke's knowledge of racing cars plays a role in the case. But just as Gabi Stein wants to contact the police, the driver is killed.