If you haven't seen it, though, read no further. For those of you who have, I would like to point out one relatively large flaw in the plot. Much is made during the final scene of Christine Helm's perjury. She even agrees with Sir Wilfred that she will go to prison, but teases, "it won't be for life, will it?"
Is it possible that neither Christine Helm, Sir Wilfred Robarts, Billy Wilder, nor Dame Agatha herself noticed the rather stunning fact that every word Frau Helm spoke on the stand was the absolute truth? The revelation of the final plot twist could have been that much more dramatic had she asked Sir Wilfred, in their moments alone together at the end, "Perjury? What perjury? I committed no perjury. Leonard was guilty as charged. And all I testified about the letters was that I wrote them, not that they were true. They can't touch him, and they can't touch me, either."
It's possible that the book ends differently, and this flaw was introduced in the adaptation. Not having the book handy, I can't verify it one way or the other.
