“KRYPTON RETURNS,” and our heroes have been sent on missions through Krypton”s history to stop H”El from dooming the universe! Superboy”s mission? Stop H”El from tampering with the history of Krypton days before its explosion. But he must also see to it that Kara Zor-El is kept safe and that the forces of the Eradicator don”t get him first.