This is an interesting concept. Bored, rich millionaires are approached by Joker in disguise and given the opportunity to indulge in a vice that they particularly love. For Bet-A-Million Bannister, it's to gamble in an exotic locale. Joker suddenly has a gambling establishment set up on a street with the sign, Shadow City. Bannister does well at first, but quickly loses a great deal of money. Joker reveals himself and has his men beat up Bannister on the street.
Batman and Robin interrupt the beating and the men get away. The next night, Bruce and Dick entertain a world explorer who is looking for his next thrill. He tells the two of Shadow City and how he plans to go there that night. The two follow him as Batman and Robin. They find themselves momentarily disoriented, but when it clears, they see they are on Shadow Street.
There, our explorer is taken into a building where the interior is out of a harem in the Middle East. But the explorer quickly catches on to the scam. He confronts Joker and before he can be hurt, Batman and Robin jump in and attack.
In the scuffle, a fire starts and Joker makes a run for it. He is caught as he tries to drive away by the two. It turns out that Shadow City was simply the interior of a building. Cars would drive down a dark street and into the building. In the darkness, the car would be elevated to an upper level where the rigged building was kept and designed.
It's a very simple story, which is a shame as it's a great premise that is never fully fleshed out. We're back tomorrow with Alfred's story in this anthology issue, Citizens!