The first prisoners Joker releases are Bruce Timm, Alan Burnett, and Paul Dini - three lead producers of Batman: The Animated Series.
The title was spoken by the Joker at the end of the episode.
This episode shows the introductions of Bruce Wayne/Batman, Alfred Pennyworth, Chief Angel Rojas, Detective Ellen Yin, Detective Ethan Bennett, and Joker.
DEBUT: Bruce Wayne/Batman, The Joker, Chief Angel Rojas, Detective Ellen Yin and Detective Ethan Bennett (episode 1.01 "The Bat in the Belfry")