Starro the Conqueror is a powerful being that creates extensions of himself that control minds. Steve Trevor, now leading ARGUS, discusses with the United Nations about Earth's heroes. News host Gordon Godfrey spreads his distrusts for the heroes. Wonder Woman is training at ARGUS, until Martian Manhunter introduces himself and warns her of Starro's invasion, which has already started. They look for Batman and the 3 of them join forces, facing Starro extensions in Gotham. Green Lantern and Flash handle an incident in Keystone City. Superman gets to Gotham and aids Batman, but Batman gets skeptical about the alliance. Lantern and Flash rush to Metropolis to face the invasion after getting an alert.
Gordon Godfrey blames the heroes for the chaos. Alfred alerts Batman of the Metropolis invasion, so Superman flies to aid Lantern and Flash. The battle gets close to a dock in Gotham where Aquaman joins the battle. As dawn breaks, Starro's extensions retreat and the heroes gather at an ARGUS facility. where Martian reveals Starro's plan is to attack Metropolis. Batman heads to evacuate Gotham, but won't join the others in the fight. The others head to Metropolis, where Starro's extensions control civilians until Superman gets controlled too. Jim Gordon persuades Batman to aid the heroes. Batman gets to Metropolis and uses kryptonite to subdue Superman, allowing the 7 heroes to unite and defeat Starro. The next day, the president honors them and introduces them as the Justice League.
