Batman: DarKnight was a sequel script to Batman & Robin, after Batman Unchained's cancellation. The idea was conceived by Lee Shapiro and Stephen Wise, that drafted a screenplay. George Clooney and Chris O'Donnell were to reprise their roles.
Despite Warner Bros. and Joel Schumacher's interest in a prequel based on Frank Miller's Batman: Year One, Lee Shapiro, a comic book fan, and Stephen Wise pitched the studio with a script titled Batman: DarKnight in mid-1998. They sent the first draft to Schumacher's company. 
DarKnight story had Bruce Wayne giving up his crime fighting career, and Dick Grayson attending Gotham University.  Dr. Jonathan Crane uses his position as professor of psychology at Gotham University and as head psychiatrist at Arkham Asylum to conduct his experiments into fear (this element would later appear in Batman Begins). During a vengeful confrontation with a colleague, Dr. Kirk Langstrom, Crane unknowingly initiates Kirk's transformation into the creature known as Man-Bat. Citizens of Gotham believe Man-Bat's nightly activities to be Batman's "bloodthirsty" return. Bruce becomes Batman "to clear his name," and solve the mystery of Man-Bat. Kirk struggles with his "man-vs.-monster" syndrome, as he longs to both reunite with his wife and get revenge on Crane, while Crane exacts revenge on those responsible for his dismissal from both Arkham and the university while encountering truths about his past.
Warner Bros. decided not to move forward with the project, and passed on Batman: DarKnight in favor of other proposals to resurrect the Batman franchise. 
- 1: Bill "Jett" Ramey (July 28, 2005). "Interview: Lee Shapiro". Batman-on-Film.