A Halloween night crime wave grips Gotham City as a slate of notorious escapees from Arkham Asylum converge on the streets, threatening to plunge the city into chaos. Solomon Grundy, Fred Tatasciore, and Silver Banshee, Kari Wuhrer, break free and quickly join forces with Scarecrow, Brian T. Delaney, as they dodge the relentless pursuit of Nightwing, Will Friedle, and Green Arrow, Chris Diamantopoulos, weaving through crowded streets and alleyways in a high-stakes game of cat and mouse. In a parallel thread, video game designer Gogo Shoto, Noel Fisher, is kidnapped by Clayface, Dave B. Mitchell, triggering a separate ransom of danger and intrigue.
A critical coup unfolds when Scarecrow and Silver Banshee steal an artificial intelligence crafted by Professor Ivo, while Grundy tears a powerful battery from the town’s atomic power plant, setting the stage for a city-wide spectacle. The Battery is loaded into an ice cream truck steered by the Joker, Troy Baker, who forces Shoto to assist in a mischievous, ominous prank meant to bend Gotham’s pulse to his will. The tension tightens as Bruce Wayne, Oliver Queen, and Dick Grayson attend an Inca exhibit at the Gotham Museum, where Cyborg, the Rose Stone’s energy-conducting promise, is revealed to the crowd. Cyborg’s display is interrupted when the Joker bursts in, and Clayface further escalates the threat by morphing into a Tyrannosaurus and rampaging through the venue.
With a citywide virus in hand, the Joker seizes control of all electronic technology in Gotham, including Cyborg, who is pulled into the villain’s dark plan and forced to help execute it. The heroes pursue the escaping cadre, yet the villains slip away, their audacious move shaping a new political nightmare as the Joker proclaims himself mayor and installs a cabinet of familiar adversaries. The trail leads the team back to the Batcave, where Batman, Roger Craig Smith, uncovers the Joker’s next gambit: a grand parade aimed at normalizing the mayhem.
Determined to halt the chaos, the heroes track the gang to an abandoned amusement park on the pier. There, they clash with the assembled villains, freeing Shoto before bringing him to the Batcave. Shoto hands Batman a device that unlocks Professor Ivo’s virtual world, a last bridge to the AI realm. The Joker’s virus plot intensifies as Batman, using Shoto’s device, ventures into the AI landscape and confronts countless copies of the same ruthless grin.
Cyborg, aided by Batman’s team and the guidance of Shoto, fights to regain control and discovers the Rose Stone embedded in his left arm. Following Shoto’s counsel, Cyborg places the Stone on the back of the Joker’s mech suit, triggering a dramatic short circuit. The Joker plummets into the sea as all electronic systems reboot, scattering the villains back to Arkham and ending the immediate crisis. Yet the city’s wounds run deep, and the Joker remains plotting his next move, the memory of the night lingering as Gotham reassesses its fragile balance between heroism and chaos.
