I recall the first time I saw this - aged ten, or so, and been terrified by the ending... Laurence Olivier is "Lieberman", a Nazi hunter who is given some detailed information from a very young Steve Guttenburg ("Kohler") that his long sought nemesis Dr. Josef Mengele (Gregory Peck) is thriving in Paraguay - and that he has an intriguing ongoing scheme that could reignite the whole Nazi movement. What ensues involves Oliver travelling to South America where he must thwart this deadly plan. Neither actor are at the top of their game, indeed for many of Olivier's scenes I half expected Neil Diamond to emerge singing "Love on the Rocks" (even if we are 18 months too early). There is certainly something menacing about the whole thing, though - the concept of human closing and the manipulation of a person's evolution is scarily depicted as the scenarios build well to my aforementioned denouement that even now, I find suitably effective. James Mason has a bit part as the Nazi henchman "Siebert", and Lilli Palmer is quite good as Olivier's daughter ("Esther") and they add a little depth to this over-long, but decently paced mystery. Oddly enough, the questions it asks have more potency 40 years after it was made, and you can't help but wonder just how conceivable this whole thing might actually be...