An unnamed spy - perhaps the same reluctant hero of The Ipcress File - is sent to Paris to deliver a file of nuclear secrets to a French doctor, but soon finds himself sucked into a twilight world of sex, blackmail and hidden motive, where friend and enemy become indistinguishable. A 'clinic' on Paris's Avenue Foch designed to cater lavishly for multiple perversions, staffed by a group of sexually and intellectually high-powered girls and equipped with devices ranging from an Iron Maiden to psychedelic truth-drugs -- that's the set-up operated by the enigmatic Monsieur Datt. Naturally, it has a hidden purpose: to compile dossiers of tape and film on influential political clients from East and West. Into this twilight world of decadence and hidden motives come the agents of four world powers.