Plot summary courtesy of IMDb:
Plot Summary for
Untitled Batman Begins Sequel (2008)
Batman, Lt.Jim Gordon and D.A. Harvey Dent team up in an effort to stop the villainous Joker, a theatrical serial killer who lives for the sole purpose of causing harm to the citizens of Gotham, as well as The Dark knight. At the same time, Batman begins to uncover more of the corruption that is plaguing Gotham City, with the arrival of crime boss Salvatore Maroni.
Summary written by Anonymous
Crime Boss Salvatore Maroni and Roman Sionis(Black Mask) are in arms deal with one of Gotham's richest men, Oswald Cobblepot (The Penguin).The Penguin works with William Earle, a man who wants revenge on Bruce Wayne for firing him.Batman with help of Lt. James Gordon and New DA Harvey Dent battle for justice but only makes matters worth with arrival of The Clown Prince of Crime, The Joker.The Joker is a brutal serial killer who murders for fun.So Batman, Jim Gordon & Harvey Dent must save Gotham from the Joker's reign of terror and death.