Superman, Batman, Green Lantern, Flash, the Martian Manhunter, Wonder Woman, Aquaman and Atom gathered under the banner of the League of Justice; together they defeated Starro the Conqueror and Professor Ivo, they repelled Darkseid and the White Martians, they explored the 850th century. They protected humanity during the "Multiple Land Crisis" and saved it from dimensional tyrants who wanted its loss, guiding it through decades of noise and fury. They are the ultimate bulwark against evil. They are invincible. What would happen if an enemy could discover their secrets and weaknesses? As they face the ultimate enemy capable of kneeling them, another question arises: who was able to provide him with such information?