The lost Legionnaires vs. a planet full of explosive sun-eaters programmed to annihilate the universe!

The missing Legionnaires decide they have to remain on the mysterious planet they found that is creating a Sun-Eater and dismantle it. Their only recourse is to destroy the planet so while they ponder that, the active Legionnaires scour the galaxy for the remaining Legion of Super-Villains members to apprehend them. The missing Legionnaires figure a way to destroy the planet and escape, so they do. Meanwhile, Laurel Kent of the Legion Academy, who has the power of invulnerability, is mysteriously shot.