Justice League vs. the Legion of Super-Heroes

"It's the 21st century versus the 31st century, with all of reality at stake! One thousand years in the future, a Legion of Super-Heroes comes together to dedicate their lives to recapturing the great age of heroes of the 21st century. When the heroes discover that reality is falling to a great darkness in both times simultaneously, the Justice League and the Legion of Super-Heroes must team up to stop it all. Soon, the Justice League are trapped...