Harley Quinn (2000-2004) #20

Last month, Superman busted in and busted up Harley's latest and greatest scheme. Now, the Metropolis story is over, and Harley has paid the ultimate price for her many sins against humanity. So where is she? And what old crimes from her not-so-distant past are going to revisit her in the worst way imaginable? To be more than vague here would only ruin the surprise.