After Harley proclaims her intentions of killing the Joker she begins to make her way into Arkham Asylum. Using Joker's Bag O' Tricks, she begins her break in. Harley uses all of her past knowledge from working at Arkahm to sneak past the security guard as well as Alice Sinner using Joker Gas. Harley runs into her final obstacle before reaching the Joker. Will she be able to get passed him with the tricks she has used to get by the others, and finally confront the Joker?