Legion of Super-Heroes: The Great Darkness Saga — Paul Levitz

This is Earth in the 30th Century. A world of peace and light. Preserving this peace is the Legion of Super-Heroes, a group of young adventurers who are the best and brightest of their kind. But a darkness is approaching; a centuries-old evil that threatens to destroy their entire universe. Herein lies the story of the Legion�s greatest challenge! Collects Legion of Super-Heroes #287, #290-294, and Legion of Super-Heroes Annual #3.