When I saw that this movie was by Graham Greene, I expected a suspense story, maybe a spy story. So I wanted to warn people that this movie is nothing like that. It is about faith and God.
It is couched as a love triangle melodrama. This disguise is so well-wrought that it seems to have fooled a lot of people into thinking the movie is a love story. But all that is merely an excuse for the rather deep philosophical issues that the movie tackles.
In typical Greene manner, though, it is rife with unexpected plot twists. For example, just when I thought the movie was about to wrap itself up, it launched into the real reason for its existence, via a flashback into "what really happened" in Sarah's life. This is an unusual place in a movie to have a long flashback, it seems to me.
After this point, there is one change of direction after another. Up until the very last scene, the movie is quite ambiguous, and it is not at all clear whether Greene views belief in God as a bad, destructive thing or not. Even the last scene does not completely resolve this question.
Johnson has a particularly unusual part, his all-consuming passion for Sarah inadvertently causing her misfortune after misfortune. His understated guilt and horror each time he discovers the effects of his actions is an interesting part of the story.
The acting by the three mains, Kerr, Johnson and, surprisingly, Peter Cushing, is top notch. This movie is not "entertainment," however. It is an intellectual challenge, engaging the viewer to wrestle with issues most thinking humans must come to terms with at one time or another in their lives.
The dialogues between Johnson and Kerr remind me very much of a non-humorous presentation of the themes dealt with in "The Screwtape Letters," with Johnson (and Goodliffe) presenting all the rational, reasonable conclusions favoring atheism, but Kerr inevitably being drawn deeper and deeper into faith in God, more because of their efforts than in spite of them.
As has been demonstrated in other comments, this movie will not be enjoyed by those unwilling to examine their stances towards these fundamental issues of human existence.
