Criminal superintendent Mark Kleinert is supposed to transfer the Turk Baran Sahin from Cologne to Istanbul for illegal possession of weapons . On the way he receives a call from his former lover Carla, who works as a luxury prostitute and wants to meet him in the city on the Bosphorus . The BKA is also currently based there officer Susanne Wahlberg. She is observed by a man named Jo Wei\u00df talking to a Turkish man in a cafe. Later, in a hotel, Jo stands in front of Carla's corpse, who also finds Mark there after him. From his Turkish friend and colleague Ibrahim Balik, Mark receives the recordings of a hotel surveillance camera and has a picture of Jo printed out back in Cologne, whom he believes to be Carla's murderer. Shortly thereafter, Mark is suspended from his service. Meanwhile, Jo drives to a remote house and finds the bodies of a woman and a girl. Also back in Cologne, Susanne Wahlberg visits her supervisor Kurt Herder during a meeting on illegal arms trafficking and tells him that Carla's mother and daughter are dead. Jo then lies in wait for her and wants to know who is behind the murders.\n\nAfter being shot at in his apartment from the house across the street, Mark finds out that Carla's real name was Maria and that he was married to Jo under his real name Rainer Simon. The murdered girl was Jo's daughter. He travels to Istanbul again to find out why his family was murdered and where several Russian missile warheads that Germany had confiscated ended up. Meanwhile, Wahlberg meets Mark at a hotel and tells him that Jo is an undercover BKA agent who once killed two of his colleagues. Mark and Wahlberg each take a room at the hotel. Mark persuades the BKA officer to have a drink with him and tells her about Carla. Wahlberg finally gives him a kiss and leaves.\n\nIn Istanbul, Jo is overpowered and abducted by several men while taking a Turkish bath. Mark finds out about Jo's kidnapping from Balik. As it turns out, Carla knew something about the missing warheads and wanted to resell her information. On Wahlberg's advice, Mark drives to his wife and children, whom he left for Carla, and makes sure they get to safety. He then travels to Istanbul and investigates with Balik's help. With a special unit they storm the hiding place of Jo's kidnappers and free him.\n\nBack in Cologne, Jo tells Mark that Wahlberg was behind the murders. Meanwhile, BKA boss Kurt Herder is meeting with the Turkish businessman Rasim Kirdar, who is simply called the "godfather" in the relevant circles. Wahlberg later visits Herder in his office and asks him if someone from the BKA is cheating on them and if it could be Jo. Herder, in turn, meets Jo in a hotel lobby and expects him to provide information if he knows anything incriminating about BKA employees. Jo then receives photos showing Carla making love with Herder and passes them on to Mark. Jo learns from Wahlberg that Herder has set up its own arms dealership network in Turkey. In addition, Wahlberg specifically put Carla on Herder, after the confiscated warheads have disappeared. As it turns out, Carla had blackmailed Herder with her information, which he also admits to Mark. Mark drives Jo to a hotel in Cologne, where Jo meets Rasim Kirdar. They are shot at from a passing car. Jo narrowly escapes death.\n\nMeanwhile, Wahlberg meets with the Turkish middleman Assad and complains that he killed Carla's mother and daughter when his job was only to investigate them. Wahlberg is finally arrested in her office. Mark visits her in prison and doesn't believe her when she says the warhead business was too tempting and things just took their course. Herder then telephoned Rasim Kirdar and discussed a deal with him that could now proceed smoothly.
