Four members of a radical ecological group are accused of the murder of the director of a chemical plant near Frankfurt. While admitting to material damage of the plant they deny any involvement with the murder. According to witnesses, five people participated in the sabotage but where is the fifth man? The defendant's lawyer hires Kemal Kayankaya to find him.

Born in Turkey but raised in Germany, Kayankaya encounters many obstacles in his search to unravel the complex riddle at the heart of this mystery, not only because he is a Turk but also because his acidic wit spares no one, not even the political and judicial powers who seem will stop at nothing to try and silence him...