Although he already has searched Iraq unsuccessfully for weapons of mass destruction as a member of a UN mission, German bio-weapons expert Arndt Wolf is still obsessed with the idea that Saddam Hussein is hiding something. Nobody around him is interested in this topic any more. This changes abruptly when an Iraqi asylum seeker claims to have been involved in the manufacture of chemical weapons. The German Federal Intelligence Service summons Dr. Wolf to ascertain the legitimacy of the claims made by the informant, who has been given the code name "Curveball".