After escaping from prison, Angolan deportee Jonathan Waputo dies in front of police headquarters. A first autopsy of the corpse revealed poisoning with aconitine. Inspectors Castorff and Holicek take up the investigation. The latter is shocked. He thinks he recognizes the Kenyan exchange student Winston Miller in the dead man. 20 years ago, he shot himself with Holicek's service pistol after being accused of hit and run resulting in death. Holicek suffered from the consequences of this suicide he was responsible for for the rest of his life. All the more he bites into the case. Despite all odds against him, Holicek sticks to his claim and tries to prove that the poisoned Waputo is actually Winston Miller. At first, Castorff was only irritated by his friend's behavior.
However, he increasingly finds himself in a conflict with public prosecutor Wanda Wilhelmi, whose tolerance for Holicek's escapades quickly wears out. More or less on itselfLeft alone, Castorff follows the trail of poisoning. He learns from the enterprising prison director Lambertz that all prisoners are supplied with vitamin preparations free of charge by the drug manufacturer Greuner-Pharma. On closer inspection, however, the alleged vitamin preparation given to the prisoners turns out to be an antirheumatic drug that has not yet been approved and contains the active ingredient aconitine. The case seems solved: Waputo was the victim of illegal drug tests. But the pathology provides a more precise finding. Waputo was poisoned with aconitine, but not as suspected from the medication administered, but with a deliberate overdose.
Castorff makes a discovery in the documents of his colleague Holicek, who has since been suspended from work, which gives the case an unexpected turn. Perhaps there is more to Holicek's claim that Jonathan Waputo is actually Winston Miller than Castorff initially thought.