Fan Casting Batman: Arkham - Episode 2: On the Trail of The Joker

Batman tracks The Joker to his hideout in a steel mill. Invading the place, Batman discovers that a doctor is kidnapped to treat The Joker. Batman rescues her, who claims the Titan is turning into the Joker's blood, slowly killing him.
Batman makes his way to the office, where he finds Harley Quinn crying over the Joker's body. Everything was a trap, and The real Joker comes from behind, hitting Batman. Harley Quinn hits him with her baseball bat, knocking the Dark Knight out.
Catwoman goes to Poison Ivy's lair, asking for help in breaking into Hugo Strange's heavily guarded vault, and retrieving her items that were seized after her arrest. Things don't work out the way she wants, and Ivy traps her with her plants.
Batman wakes up tied. The Joker explains that he transfused his blood to Batman, infecting him with the disease. He says he sent samples of his blood to Gotham hospitals, forcing Batman to find a cure.
The Joker pushes Batman through the window. Batman stands up, with a cell phone strapped to his chest, which The Joker will use to communicate. He indicates that Mr. Freeze has the cure. Batman begins tracking the coldest spot in Arkham City to find him.