Isabelle Wayne is the sister of Bruce Wayne who decides to make an unexpected visit to Gotham and decided to stay. While Bruce is the rich business man she's known as the little rebel who's friends with people like catwoman and poison ivy. This catches the attention of the joker when he sees she has become involved with arkham asylum as well and that he become somewhat infatuated with her in the past.

"Meet me at the Motel down the street" he said as he handed me a set of keys that had what I assumed to be a room number on them. "Why?" I asked confused. "You'll find out."