The questions aren't always simple. In one episode a murderer who works in an important war department argues rather eloquently that Foyle shouldn't turn him in because he's doing important war work and, after all, it was only a German woman that he murdered. Foyle didn't buy it. In a different episode, the father of a young murder suspect begs to borrow his son temporarily to help him take his fishing boat across the channel to save some of the soldiers from Dunkirk. He promises he will return him to Foyle afterwards. Foyle accepts.
Part of what I appreciate about this series is that it portrays rather honestly the awfulness and complexities of the times in which it's set and yet helps us see that it is possible to choose well, even in such circumstances.
This reminded me of a piece from Pope Benedict's encyclical on hope that we discussed with the teen catechism group last night. It's about freedom and the application of truth that changes to some extent with each generation because they are dealing with ever new and complex issues.
The right state of human affairs, the moral well-being of the world can never be guaranteed simply through structures alone, however good they are. Such structures are not only important, but necessary; yet they cannot and must not marginalize human freedom. Even the best structures function only when the community is animated by convictions capable of motivating people to assent freely to the social order. Freedom requires conviction: conviction does not exist on its own, but must always be gained anew by the community.
Since man always remains free and since his freedom is always fragile, the kingdom of good will never be definitively established in this world. Anyone who promises the better world that is guaranteed to last for ever is making a false promise; he is overlooking human freedom. Freedom must constantly be won over for the cause of good. Free assent to the good never exists simply by itself. If there were structures which could irrevocably guarantee a determined - good - state of the world, man's freedom would be denied, and hence they would not be good structures at all.
What this means is that every generation has the task of engaging anew in the arduous search for the right way to order human affairs; this task is never simply completed. (from paragraphs 24 and 25, Spe Salvi)
Note: The murders lean a little on the gruesome side at points. I'd be more confident recommending this to older than younger teens.