The Silent One 1973 Le Silencieux

Hitchcock himself is finally rivalled.

Who is Anton Haliakov, who has just been abducted by the M.I.5 in London? A Soviet scientist apparently. But sixteen years before the man had another identity, Clément Tibère, and another nationality, French. So what led him to become Russian and to change identity? And why are the British secret services interested in him?