T.O. Morrow rules the world in the year 2000 due to changes he made by traveling to the past. The Flash (Jay Garrick) tries to make his JSA teammates see what has happened, but they refuse to believe him. The JLA, having traveled to the past, and been imprisoned makes their escape. The JSA's descendants, corrupted in the new timeline, attack Professor Morrow's citadel to take control of the timeline for their own good.
The JSA finally sees reason and teams-up with the JLA to defeat Morrow and set the timeline right again.