Hmm... the mention of Strange and Scarecrow gives me another idea...
Film 4: The Scarecrow
attempts to cause widespread fear throughout Gotham, but is foiled repeatedly by Batman. Crane wants Batman to know fear. He allies with Hugo Strange
, who has discovered Batman's true identity as Bruce Wayne. Discovering the truth to Batman's tragic past, Crane and Strange send genetically altered "Monster Men" to capture Batman and lock him in an abandoned wing of Arkham. Locked in as well are three families, each with two parents and a small child, caught in a death trap - the idea is that each child will have to witness his parent's murder, and Batman will not arrive in time to stop it. Batman must think through the fear toxin, escape Strange's monster men, and save each family in time (which, of course, he will. He's Batman
). In the end, Scarecrow is made insane by his own fear toxin, forgetting Batman's identity because he is so fearfully fixed on the Batman persona. Strange will be destroyed by his own monster men.
The theme of course would be something like Courage in the face of Tragedy.
That's four films there with no Joker yet!