They thought the threat was over. But it had only begun. And it makes strange bedfellows.

Trapped in another dimension, the Golden Age Flash teams with the Modern Age Green Lantern and vice versa to solve some very dire problems:

Problem One: An alien invasion is on the verge of taking over the Earth.

Problem Two: The younger heroes seem to have switched powers if not identities.

Problem Three: One hero may be running his final race.