Harley Quinn: Our Worlds at War (2001-) #1

The insanity of Harley Quinn's world collides with the metamorphic sanity of Superman's Pal Jimmy Olsen in an explosive way! Jimmy's returned to Earth with information vital to the war effort, but tragically, he's landed in Gotham, where no one believes him. Now he has to depend on Harley to get him to Metropolis in one piece. Poor guy.