The story so far? When the hero Shazam entered Khandaq in order to spread the ashes of his fallen enemy Black Adam in the sands of the villain's home country, the Justice League (Superman, Batman, Wonder Woman, those guys) sprang into action, hoping to avoid an international incident by kicking Shazam out of Khandaq. At the same time, the Justice League of America, a team of second-stringers assembled by the government agency specifically for the task of taking down the other Justice League, arrive with the same idea.
In the midst of all the arguing that ensues, Superman suddenly loses control and uses his heat-vision to kill Dr. Light, a member of the rival of America League. Superman surrenders himself and is imprisoned by Amanda Waller, leader of the ARGUS (Strategic Hazard Intervention Espionage Logistics Directorate) and the of America squad, and all the Leaguers convene to try and figure out what exactly what happened between Superman's eyeballs and Dr. Light's face.