The At the most recent Justice League meeting, all members are present except for Batman, Aquaman and the Atom who are busy with other cases. With no imminent dangers, the League decides to check their mail. They find letters from Bruce Wayne (puzzling Superman who knows Batman's secret identity) asking the League to check out word of an invisible thief, a letter from Ray Palmer asking to check out a mysteriously firing cannon, and a letter from C. King to check out a disappearing island. The present Justice League members decide to look into the reports.
When Green Arrow, Flash and Snapper Carr appear at Wayne manor to ask about the letter, they find out that Bruce Wayne did not write the letter, prompting Bruce to drop his current case to help out his fellow Leaguers solve the mystery. The same situation happens when Wonder Woman and Martian Manhunter visit Ray Palmer, and Superman and Green Lantern visit C. King (Aquaman in an assumed disguised to try and catch smugglers.)
In Gotham City, Batman helps Flash, Green Arrow and Snapper try to capture the "invisible" thief from robbing an art gallery however they are captured by strange tentacles coming out of a portal and sucked away before they can solve the mystery. Same thing happens when Atom, Wonder Woman and Martian Manhunter detect a strange explosion that happens at the same time as the cannon going off, and Superman, Green Lantern and Aquaman try to learn the secret of the disappearing island.
The League finds themselves in another universe and are standing before an omnipotent being who they begin referring to as "I". I has brought the JLA to his reality to effect the group so that if they ever fought in groups of two or more, they would fail, as their continued team-work and success caused a "Robber-Energy" that threatened to render I inert should the group have one more successful mission. Unable to kill them, I did the next best thing: Make it impossible for them to use their powers in unison. Unable to defeat I, one-on-one the entity returns them back to their own reality.
There, Snapper comes up with a way to beat I: By having having Green Lantern revive Amazo and forcing the being to use all it's powers it copied from the JLA. This causes the same reaction and I is rendered inert, with I defeated, the JLA are able to work as a team again. They work together to defeat Amazo, and return his inert body into their trophy room. With the threat of I ended, the group then solves the mysteries they began:
