El destino del planeta Tierra pende de un hilo cuando los miembros de la Liga de la Justicia se enfrentan a una nueva y peligrosa amenaza: los denominados "Fatal Five".

Lex Luthor is frozen during a battle with the Justice League. He thaws out in the 31st century, discovers Time Trapper and prevents Superman's arrival to Earth as a baby. Future teen heroes Karate Kid and Dawnstar must stop him.

The Flash finds himself in a war-torn alternate timeline and teams up with alternate versions of his fellow heroes to return home and restore the timeline.