“The Dark Knight begins with the Joker robbing a huge bank (we’ve seen photos of this everywhere). The bank is where the mob and all the gangs in Gotham keep all of their money. The Joker takes this money and holds it “ransom”. The Joker then says to the mob and the gangs of Gotham, “If you help me take down Batman, you’ll get your money back. If not, I’m going to burn it all.” This is how the Joker assembles his army to take down Batman.”