Harley Quinn (2000-2004) #25

Batman guest-stars as the moment fans have waited for since issue #1 arrives at last! The Joker returns with something less than romance in his heart. Harley may have renounced him, but did she really mean it? And given that this is the Joker, you know nothing is going to be as it seems, as he launches a scheme that will have readers and Batman guessing until the end.