Istvan Kaltenbach is an unscrupulous arms dealer. No court in the world has ever been able to prove his involvement in this murderous business. Together with his beautiful daughter Sharon he lives a quiet life in a dreamlike villa in southern Portugal. But peace in Kaltenbach's home is threatened. The German Federal Bureau of Investigation BKA has succeeded in putting together a file proving that Kaltenbach was involved in the construction of a toxic gas plant in Iran. The BKA threatens to use this file against Kaltenbach should he refuse to comply with the wishes of Dr. Goetz, a BKA staff member. According to information in the possession of the BKA, three nuclear warheads are to be sold on the international black arms market. Kaltenbach is to introduce himself as a front man and pretend to be interested in buying the warheads. Thus the BKA hopes to find out the identity of the sellers. Journalist Tom Severin is also interested in Kaltenbach's activities.