Superboy; Klax-Ar (villain); Jor-El (flashback); Krypton (flashback); Lana Lang; Jonathan Kent; Martha Kent
Klax-Ar, a Kryptonian villain appears, claiming to have destroyed Krypton with a "sky mine", he threatens to inflict the same fate on Earth unless Superboy agrees to exile himself from his adopted planet.
Superman; Jimmy Olsen; Professor Crane; Jor-El; Lara; Baby Kal-El; Krypton; Krypto
Jimmy tests a time machine and finds himself on old Krypton where he lands a job as baby Superman's babysitter. When he returns to his own time his memory of the trip is erased but the by now grown up Superman remembers all.
Superman; Lois Lane (also as Rama); green kryptonite (flashback); Jor-El (flashback); Krypton (flashback); Batman (also as Clark Kent)
Lois poses as Rama, a survivor from Krypton, in order to find out Superman's secret identity. But after he reveals his identity, Superman realizes that Rama is really Lois and has to rely on the help of a friend to restore his double identity.