^what? really? not being a dick, i'm just not sure if u are joking or not....
...i think the classic mad-hatter story would be fine. Crazy genius never had any friends as a kid, was always made fun of.... is obsessed with "alice's adventure in wonderland" and begins speaking in rhymes. doctors determine that he is unstabe and dillusional so they send him to arkham. after some addition "help" from the joker, the hatter escapes.
it is halloween and young barbara gordon (who has just moved to live with her adoptive father, jim gordon) disobeys gordons orders not to go trick-r-treating. she is chaced by thugs who intend to do unspeakable things to her. the mad hatter saves her and takes her to his "wonderland" where she is to be his Alice. when she refuses, Hatter becomes increasingly discourteous.
Gordon rebuilds the bat symbol to call batman and get his help. of course they have been secretly meeting already, gordon just takes advantage of the opportunity to openly talk to batman.
It is batmans (and maybe robin?) job to find her. Of course batman saves the day.... and having saved gordons daughter, begins to restore his good name with the people of gotham.
dont think this should be the main story of the third film...but could be a fun side story.
oh, and for cast??? maybe Ben Foster? he can play a GREAT crazy person