A scientist asks the Legion to help him capture what he claims is a dangerous creature, but both the creature and the scientist have a dark secret.

It is the 31st century. A group of super heroes called the Legion of Super Heroes travel back in time to recruit earth's greatest super hero, Superman, to help fight the evil of their time. While their intentions were good, good intentions don't always produce good results. Instead of bringing back Superman, they retrieve a young Clark Kent from his farm in Smallville to the future.

Superman makes a new friend, Alexis, but his new chum soon becomes obsessive about having Superman as her only friend and not sharing him with anyone else...including the Legion.

Superman accidentally opens a portal to a phantom dimension, unleashing a teenager with powers that match his own who eventually traps the other Legionnaires there.

Lightning Lad enters the Intergalactic Games and must compete against his greatest rival.

A Legion team is forced to take refuge in a derelict space station but are separated and begin disappearing one by one.

Brainiac 5 is forced to get ahead to lead two of his teammates to a planet where the only cure for his faltering IQ can be found.

Lightning Lad resigns from the Legion to join a new team, but soon finds himself caught in a conflict of interest when the two teams end up opposing each other.

When the Legion are tied up fighting a horde of creatures consuming the Earth's ionosphere, the rejects from the yearly Legion Auditions are the only ones standing between Earth and total destruction.

When a young sorcerer comes to Earth and wreaks havoc, particularly on a magic-vulnerable Superman, Phantom Girl must try to convince his elders to reign him in.

At a moment of crisis, Cosmic Boy returns to lead the Legion, accompanied by a mysterious new hero.

The ancient organic weapon known as the Sun-Eater has been unleashed, and it lives up to its name. It heads toward Earth's sun and not even the Legion can stop it.

The Legion must turn to help from their greatest foes when they are unable to stop the Sun-Eater themselves. Meanwhile, Superman confronts the Sun-Eater's controller but even he may be powerless before the alien.