Armed with Hawkman’s repellor-discs, which prevent Starro from taking control of them as he has their fellow members, Batman, Aquaman, the Flash, Hawkman, Hawkgirl, Elongated Man and Zatanna mount a counterattack on Starro and his mind-slaves. If they fail, the authorities may be forced to destroy New York to prevent the spread of Starro’s endlessly replicating duplicates. The problem is solved by two “victims” who escape Starro’s control. Red Tornado, whose computer mind is not affected as a human brain would be by Starro’s influence, blacks out the city, leaving Starro without an energy source, and Terry Watson, by hiding in a food freezer, enables Hawkman and Hawkgirl to discover that intense cold can not only free the alien conqueror’s victims, but also defeat Starro himself. Firestorm and Green Lantern, their minds freed from Starro’s control, bombard him with ice and freeze him solid, while Zatanna’s magic chills the air, disposing of the duplicates across the city.
Starro, the Starfish Conqueror, has mentally enslaved the entire population of New York City, including six members of the Justice League of America. Aboard the USS Truman, the Justice League of America close in on New York City. The Admiral has orders to employ nuclear weapons, to keep Starro, the Starfish Conqueror, from enslaving the rest of the world. The Justice League of America is given a few hours to resolve the crisis, before the Navy takes action. Starro, the Starfish Conqueror, establishes it's base of operations in Grand Central Station. Starro, the Starfish Conqueror, orders Firestorm, the Nuclear Man, to transform the marble floor into steel.
Superman tears up the electrified third rail, and feeds it into a transformer, created by the Green Lantern's power ring. The transformer transfers the electricity of the third rail, through the steel floor, to Starro, the Starfish Conqueror, feeding the alien horror. Starro, the Starfish Conqueror, sets about replicating miniature versions of itself, to enslave all of humanity. The Red Tornado departs Grand Central Station. Unbeknownst to Starro, the Starfish Conqueror, the Red Tornado's computer mind is immune to biological domination. The Red Tornado makes a run for it, only to be attacked by Wonder Woman. Reluctantly, the Red Tornado subdues Wonder Woman, then makes good his escape.
The Hawkman outfits the Justice League of America with repeller discs, designed to keep the replicants of Starro, the Starfish Conqueror, at bay. Aquaman is tasked with keeping Starro, the Starfish Conqueror, from spreading it's influence by sea. The Hawkgirl, and the Hawkman, are tasked with keeping Starro, the Starfish Conqueror, from spreading it's influence through the sky. The Batman, the Elongated Man, the Flash, and Zatanna make their way to Grand Central Station. Terry Watson, the first person to be enslaved by Starro, the Starfish Conqueror, steps into a meat locker and regains his free will. Watson, terrified, hides away inside the meat locker.
Aquaman telepathically orders the denizens of the sea to disable all boats trying to leave the harbor. Aquaman then savagely subdues the crews of those vessels. With the Elongated Man scouting the way, the Justice League of America make their way to Grand Central Station, via the New York Subway System. The Batman, and the Elongated Man, have suspicions that something is going on between the Flash, and Zatanna. Both heroes respect their teammates' privacy, and decide not make inquries. Zatanna fears the Flash has regrets regarding their time together. A swarm of replicants floods the subway tunnel, knocking the Batman down a flight of stairs.
The Flash, and Zatanna destroy the replicants. The Elongated Man notices the toll casting spells seems to have taken on Zatanna. Zatanna asks the Elongated Man to stay silent on the matter. The Justice League of America split up to cover more ground. The Red Tornado approaches a power station, in the North Bronx. After dealing with the enslaved guards, the Red Tornado tries to shut down the power grid, to starve Starro, the Starfish Conqueror. Feedback fells the Red Tornado. The Hawkgirl, and the Hawkman, take out a communications helicopter, carrying replicants. The Hawkgirl, and the Hawkman, discover Watson, cowering in the meat locker.
The Batman confronts the Black Canary. Though enslaved by Starro, the Starfish Conqueror, the Black Canary is still a formidable match for the Batman. The Batman manages to subdue the Black Canary, but finds that he cannot remove the replicant from her face without killing her. The Red Tornado shorts out the power grid, blacking out Manhattan. The Justice League of America confront Starro, the Starifsh Conqueror. Having discovered the alien despots's weakness to extreme cold, Firestorm, the Nuclear Man, and the Green Lantern combine their power to freeze Starro, the Starfish Conqueror, ending the crisis.