Dr. Marion Röder, the youngest surgeon at the Omega Hospital, is harassed by her drunken ex-boyfriend, orthopaedic surgeon Dr Jürgen Mattes, at a birthday party for a colleague of theirs. That same night Dr Röder is found dead in her own home by a friend of hers, Laura Finke. Her throat had been cut. Dr Mattes can't produce an alibi and is arrested. The director of the hospital, Theresa Hirsch, and her husband Alexander, a successful banker, are both staggered by the death of the young doctor; they were good friends of hers.
Lessing takes the job of defending Mattes. But it is a difficult task: Mattes claims to remember nothing of the evening in question and doesn't offer any helpful information. What exactly is Mattes trying to hide? Circumstantial evidence against him mounts up when his fingerprints are found both on the murder weapon and at the crime scene. What's more, the victim's friend, Laura Finke, points the finger of blame at Mattes - and a trace of his DNA is even found under the victim's fingernails. Was it a crime of passion - did he murder Röder because she rejected his love?
But now Matula finds evidence that there were other men in Marion Röder’s life. And the shady businessman Christoph Arend, a wholesaler for medical equipment, comes under suspicion when Martin surprises him at the crime scene, going through Röder's desk. Arend, who is married, admits that he was having an affair with the victim - but is that the truth? Or is he trying to conceal something quite different? Matula does some research and establishes that contaminated medical equipment from China, which Arend supplied to the Omega Hospital, had led to the death of a patient. Dr Röder was in the process of exposing the scandal. It now emerges that Dr Mattes has been thinking along the same lines: he manages to escape from prison and makes his way to Arend's house, intent on forcing him to confess. But Matula stops Mattes and persuades him to leave this to the forces of law and order.
However, now evidence about a completely different relationship involving the dead surgeon begins to emerge: Matula comes across photographs showing Marion Röder secretly meeting a man in Zurich. Was this the love affair that led to the tragic death of the young woman?