That goofy, sexy, curvy little clown's assistant is at her old trick and treats in this monthly issue all her own. In this issue we see Harley posing as Poison Ivy in order to get into Arkham to release the Joker, her puddin'. The Joker gets a little bit hurt in the rambunctious escape attempt by Harley so they go to his hide out. Meanwhile, a man by the name of Mr. Happi is rebuilding the old amusement park, Happyland. He is going to turn it into a modern day theme park complete with a live show about Batman busting the baddies. Back at the hide out, the Joker really isn't injured and finds out about Mr. Happi's plan to open the park with a rollercoaster named after him. So he sends Harley and some goons to sabatoge the coaster. Harley takes over the whole process of sabatoge and the Joker doesn't like being cut out of the action. He's jealous. At the park, the real Poison Ivy drops by and tells Harley that she's crazy to trust the Joker, let alone hang out with him. But Harley just bounces away thinking thanking her. At the park the Joker abducts Mr. Happi and his wife and puts them on the killer coaster. The Joker then turns on Harley and shoots her. But it is not the real Harley! It was Poison Ivy disguised as Harley. Upon witnessing this, Harley beats up the Joker's goons and tells the Joker that she did some sabatoging of her own by making the coaster destroy itself. She then draws the Joker into a neon sign. The Joker is re-arrested and Ivy and Harley sit and talk.