Batman in his 10th year of crime fighting woukd find the "Red Hood" who was actually Jack Napier, Jack would be insane, and crazy about batman, he would recruit a group of followers including Harley Quinn. Batman, Robin and Batgirl would stop the Joker Gang, Joker would fake his death, Robin would leave Batman's shadow.
Post Credit Scene 1: Oliver Queen picking up his bow.
Post Credit Scene 2: Joker's echoing laugh