Batman and Robin are invited to a secret demonstration hosted by Professor Hugo Strange and his assistant, Dr. Harley Quinzel, who could change the future of Gotham forever. Along the way, Batman stops at Gotham State Penitentiary to visit Catwoman (whose suicide attempt failed) and give him a poem book by Elizabeth Barrett Browning to keep her busy until she’s released there.
At the lab, they meet with Harvey Dent’s prosecutor and ally against crime, Harvey Dent, who has become famous for a case involving counterfeit coins. Hugo Strange thinks that good and evil can exist in the same person and conceived a “Evil Extractor” through which volunteer criminals, such as Joker, Penguin, Riddler, Egghead and Mr Freeze, will be purged of evil. Batman feels an aberration, but Strange presents his experiment anyway despite the fact that by this method he virtually leaves the judiciary without work.
Everything follows the plan until Joker urges his comrades to overload the machine. Observing this, Professor Strange asks Quinzel to stop the machine … but it’s too late, and Harvey falls victim to an explosion that causes terrible scars on the left side of his face. Harvey, now nicknamed “Two Faces”, starts in a series of crimes. He is finally taken to a hospital where his face is reconstituted and his mental health seems to have been restored in turn.