Wow, that was fast! Apparently there is a version of me out there that's actually weird & bored enough to kind of make such a thing happen. Watch! Here's the summary,
The promising psychiatrist Dr. Harleen Quinzel, of Arkham Asylum, is commanded by Jeremiah Arkham, the new director, for treating the Joker. She and her new patient have long and deep talks about his vision of life and world, and his persuasion starts to convince her gradually. After several sessions with him, she cant stop of thinking about him, but not in a professional way. She also dreams and fantasizes with him (images in sepia are her thoughts remembering her moments with him).
Then he takes one of the Arkham guards as hostage, forcing her to release all the inmates in Arkham. Mr. Zsasz, a serial killer, is going to attack her but then a bomb (set by the Joker) explodes opportunely. Joker approaches Harley (who is unconscious but unharmed), with what seems intention of killing her but in the end he doesnt. He escapes, leaving her horrified and shocked.
When Jeremiah Arkham blames her for negligence (it looks like she helped him on purpose, when thats not true or is it?) and fires her, she realizes two things:
One, the Joker was right - the world is chaos and a twisted joke.
And two, she is hopelessly in love with him.
So she decides to change. She leaves her home and her life, puts on a costume and names herself Harley Quinn (I would have liked to make her wear make up like him, but you have to work with the video stuff you have u_u). Then she goes to find him and prove him they are soulmates. Will he accept her by his side? We see hes kind of smiling at the final scene, when he sees her...
The Joker: Heath Ledger
Harleen Quinzel / Harley Quinn: Rosamund Pike
Jeremiah Arkham: James Cromwell (hes perfect for the role check it out in Arkham Asylum Living Hell comics)
Victor Zsasz: Tim Booth (from Batman Begins)