Filmed on location in Zurich, Switzerland, The Swiss Conspiracy is concerned with a Swiss bank that discovers some of its clients are becoming the victim of a brilliant blackmailer. The bank's president (Ray Milland) contacts David Christopher (played by David Janssen), a former agent with the U.S. Treasury, to help discover who the blackmailer is and to foil his plot. As Christopher delves into the mystery, he uncovers a complicated web of intrigue, car chases, and shoot-outs that takes all of his wits to unravel. Along the way, Christopher encounters the beautiful Denise Abbott (Senta Berger), with whom he develops a relationship, as well as Rita Jensen (Elke Sommer) and Robert Hayes (John Saxon), who know more than they are willing to tell.