The Legion of Super-Heroes learn that the Khunds intend to destroy the planet Earth.
Paul Levitz has been acclaimed as a favorite Legion of Super heroes writer, his popular "The Great Darkness Saga" (Aug - Dec 1982) often being cited as a high point in his output. However, he demonstrated his great affinity for the Legion, plus an uncanny ability to structure intricate subplots into a single storyline, four years earlier when he and James Sherman waged "Earthwar."
"Earthwar" spanned 5 issues, making it easily one of DC's longest story arc's so far. The ambitious epic significantly magnified the Legion's role as cosmic peace keepers, the magnitude of their missions - and the consequences. It all began with the Legion's ranks spread thin amid a series of seemingly unrelated incidents. On Weber's World, Wildfire, Dawnstar, Mon-El and Ultra Boy uncovered subversives and sabotage at a peace summit between the United Planets and the Dominion. Meanwhile another contingent of Legionnaires defended Earth from the Resource Raiders, galactic pillagers who were actually advance scouts for Khundian forces planning an assault on the planet.
Levitz's subsequent issues revealed that other forces were escalating both problems. Upon taking the fight to the Khundians, Superboy and the Legionnaires learned of the involvement of the villainous group, The Dark Circle. Simultaneously, Earth's final line of defense fell to the retired Legionnaires Lightning Lad, Saturn Girl, Bouncing Boy and Duo Damsel; Science Police Officer Shvaughn Erin (her debut); and the Legion of Substitute Heroes.
When the Legion defeated the Dark Circle, Earthwar's true architect was revealed: longtime Legion foe, Mordru the Merciless. Mordru nearly won the war, but Element Lad transmuted atoms in space to bury him alive - the Legion's greatest victory.