I've been talking a lot about "morality" in fiction, and I even invented a term to describe a particular way of portraying "morality". But there's a problem here: many people who might read this won't even know what I mean by the word. Most people tend to think of morality as a set of rules about what isn't allowed. Others tend to think of morality as a set of abstract rules that are applicable universally to human decision-making. Both groups tend to think of moral deliberation as debate over the correct course of action in some hard case. (The classic example of this is the Trolley Problem.)
"Morality" as I'm thinking of it (and I'm not alone in this) is much less about abstract universal rules (whether the Ten Commandments or the Principle of Utility) than habits of behavior, the regulation of emotions, and the ranking of priorities. Morality is about what makes people good, and what makes people good isn't conformity to a set of abstract rules, but the perfection of their humanity. So, what perfects humanity? To put it vaguely, it's good habits, proper priorities, self-control, and observing justice in relation to others.
So when we talk about moral education in film, we're not talking about commendations of abstract rules, or portraits of difficult cases. Christopher Nolan's The Dark Knight is a great illustration here. The film provides a series of impossible alternatives and moral dilemmas for the characters to solve, but has virtually nothing to do with the practice of virtue. In this way it manages to throw a spotlight on moral casuistry while teaching us next to nothing about the perfection of human nature or the cultivation of good habits.
People often gripe about how boring morally good characters are. I've never understood this idea. Perhaps it comes from the notion that moral goodness is primarily a negative characteristic: it describes almost exclusively the things someone does not do, the rules he does not break, etc., and beyond this perhaps it has a suffocating veneer of smiley humanitarian benevolence. Granted, this idea is very unappealing. But the real moral hero isn't a bland, "straight laced do-gooder", it's the person who dominates all his inclinations, confronts every situation with thoughtfulness and a readiness to suffer for what's right, and maintains equity in all his relationships according to their kind. This sort of morality doesn't constrain, and isn't negative — it liberates, and it provides greater scope for the cultivation of the distinctive excellences of the individual by supplying him with all the power of a well-conditioned will and a patient mind.