The American scientist in question is named Michael Armstrong, played by Paul Newman, and he is aided in his mission by a fellow scientist and former lover, Sarah Sherman, played by Julie Andrews. The two travel to East Germany under the guise of attending a scientific conference, but their true mission is to obtain the formula for a new type of radar absorbent material that they believe is in the possession of a renowned East German scientist, Gustav Lindt.
However, once they are in East Germany, things quickly start to go wrong. Michael finds that he is being followed and monitored at all times, and his supposed contact with Gustav turns out to be an uncooperative government minder. Meanwhile, Sarah grows increasingly suspicious of Michael's motives, especially after she discovers a notebook containing coded messages and realizes that he has been lying to her about his activities.
As tensions mount and their relationship becomes strained, Michael and Sarah must find a way to complete their mission and get back to the West. This involves a tense and thrilling sequence in which they attempt to steal the formula from Gustav's laboratory, aided by a sympathetic farmer and his family.
Torn Curtain was directed by Alfred Hitchcock and released in 1966. It was widely regarded as a departure from his usual style, with a more realistic and down-to-earth approach to the spy genre. The film was not a major commercial success but has since been reappraised by many critics and fans as an overlooked gem in Hitchcock's filmography.