Imperiex begins his conquest of the 31st century by freeing the Legion's greatest enemies from prison. The team must look to Superman in the 21st century for help, and Superman comes to the future only to meet his 41st century clone, Kell-El.

When only one applicant makes it through the Legion testing, Superman decides to recruit a new member: the non-powered master of martial arts, Karate Kid.

On a mission to the last surviving outpost of Krypton, Superman learns how Brainiac 5's ancestor was the one who participated in the destruction of his homeworld.