The Half Moon Club was a defunct establishment.
The exact operations of the club are unclear, but it was once a popular spot for Bruce Wayne and his friend Harvey Dent. The club was later abandoned and possibly set for destruction. When Dent was about to undergo an operation to restore his face, he recalled how much he enjoyed hanging out at the club. However, Two-Face refused to allow his other persona to get rid of him all together, so he arranged for his thugs to break Dent out of the hospital. He used the Half Moon Club as a hideout, where Batman tracked him down, but Two-Face set up a trap and chained him to a crane. Before Two-Face could set off some dynamite connected to the crane, Batman escaped and a fight ensued. The dynamite's detonator was accidently turned on, but Batman was able to save himself and Two-Face just as the explosion occurred.