With the help of a nefarious billionaire, the Joker and Harley Quinn hatch a plan to lock up the Justice League for good. First they'll kidnap The Flash and Huntress. Then they'll lure the Justice League's most powerful members including Batman, Superman and Wonder Woman into a trap beneath Arkham Asylum. Can the world's greatest team of super heroes thwart the Joker and Harley before it's too late? Or will this perilous pair doom them forever to a Justice League prison?