Batman: The Animated Series - Season 1 Episode 31 -

Batman is incarcerated in Arkham Asylum after being exposed to the Scarecrow's fear-inducing gas. Batman knows that the Scarecrow has escaped for the second time and is planning to poison Gotham's water supply with the same fear-inducing gas. Can Batman bring himself to break the law and escape from Arkham before the Scarecrow brings Gotham to its knees?