Sebastian (Dirk Bogarde) is an undisciplined mathematics genius who works in the "cipher bureau" of the British government. While cracking enemy codes, Sebastian finds time to romance co-worker Susannah York. The film dwells upon Sebastian's rather lax morals (even by 1968 standards), culminating in his refusal to commit himself to York once he's rendered her pregnant. This aspect of the story is frankly more fascinating than the main espionage plotline. Keep an eye out for Canadian actor Donald Sutherland in a bit as an American.
~ Hal Erickson, All Movie Guide