It's almost Halloween in Gotham City, and Batman, Robin, Batgirl, Jim Gordon and Harvey Dent are investigating a series of murders at the hands of the mysterious "Holiday Killer", as well as a puzzle-obsessed cyber-terrorist known as The Riddler, who with help from Arkham Asylum's crooked warden Hugo Strange, breaks the cities most dangerous criminals out. The Joker and Penguin also show up, cashing-in on the cities panic-stricken takeover, with help from The Mask.
