The psychology lecturer and family man Bernd Stach, convicted of murder, is able to escape from prison after attempting suicide. While the manhunt is already running for him, he already has Ellen Lucas in his sights. She led the investigations that convicted him as the perpetrator. He overpowers Inspector Lucas while jogging and kidnaps her. It quickly becomes clear that Stach isn't out for revenge, but rather to convince Lucas that he was the victim of a miscarriage of justice. Despite the danger she is in, Ellen tries not to be intimidated by Stach and listens to his arguments. When Ellen's colleagues find her and free her, Stach escapes at the last moment. The encounter with Stach left its mark on the inspector.
In addition to the search for Stach, she takes up the old investigations again – despite the skepticism of Chief Inspector Boris Noethen. The main witness for the prosecution, Marie Heusler, who claims to have observed Stach during a party with the victim, is still absolutely sure of her case. Niklas Brettling, whose testimony incriminated Stach, is also interrogated again. Bernd Stach is arrested while trying to assure his little daughter of his innocence. Ellen now has serious doubts about his conviction and continues to press ahead with the investigation. She is amazed that Marie's testimony in court a year ago was not more questioned. Lucas' path leads to Prof.
Kellermann, highly decorated psychology professor and court expert who examined Marie Heusler's testimony in court and still considers her testimony to be credible. Lucas initiates a new crime scene inspection with all witnesses - which makes Marie Heusler very insecure. In addition, Niklas Brettling does not appear for the crime scene inspection. Chief inspector Tom Brauer researches Niklas' background and learns that the orphan Brettling was supported during his time in the children's home by an organization whose board is Kellermann. Marie breaks down shortly thereafter and confesses in conversation with Lucas that Professor Kellermann should never have acted as an expert: The unstable Marie was already in therapy with Professor Kellermann before she testified against Stach.
Inspector Lucas has far-reaching suspicions and is researching on thin ice with Chief Inspector Judith Marlow: Is it possible to manipulate witness statements? And if so, who would benefit from it? Lucas' courageous path takes her deep into the psycho-systemic structure and thus directly to the perpetrator.

After a fire, the body of Josef Gerlach, who lived in constant conflict with environmental activists, is found. Ellen Lucas and her team take up the investigation. Gerlach farmed large areas of grain with his brother Reinhold. A mobile phone video shows an argument with the young activists David Buske and Marie Bacher. Angry, they demonstrated against the poisoning of the fields. Together with their classmate Paul Krenn, the three form the "New World" group, which advocates a radical change in agriculture. Lucas and Tom Brauer take on the three high school graduates, but they deny having anything to do with the arson. A look at the finances shows that the Gerlach farm is heavily indebted, and Josef Gerlach had taken out a high term life insurance policy, which could be a motive for Reinhold.
The next morning, Paul Krenn is found dead in the woods – his neck broken. Lucas blames himself. Did she miss something? She questions Marie and David, who are shaken but pretend not to know. Traces of an off-road vehicle are discovered at the crime scene. Since Reinhold Gerlach drives such a car, Tom looks him up. He finds him drunk. Even if the evidence against him is increasing, Lucas does not believe that Gerlach was the perpetrator. She stays close to the young people and finds out that there was a fourth member of the "New World" group: Hanna Manz. Since a bicycle accident, she has been in a wheelchair and now goes her own way. She states that she left the New World group when she became too extremist.
Lucas and Judith only found out about an internship that the now dead student was doing at the pharmaceutical company NeoX from Paul's father. Did the teenagers have a secret plan? And was Paul perhaps a spy in the company? Lucas and Judith interview Martina Thiel, founder of NeoX, and learn that the company is about to launch a revolutionary new compound, phytosate. According to Thiel, it works in a similar way to glyphosate, but has no negative impact on the environment. Unlike his colleague Thiel, Dr. Lammert, who had the intern Paul under him, was shocked by his death. When Marie and David also disappeared the next day, Lucas was alarmed.