A super-powered young man named Ultra-Boy has arrived in Smallville with his guide Maria Latham, for the purpose of trying to learn the secret identity of Superboy. Mingling in with the youth of Smallville, Ultra-Boy attempts to learn Superboy's secret identity, at first asking Superboy's confidant Pete Ross. This cause Pete to worry about accidentally revealing the fact that he knows Superboy's secret identity.

Meanwhile, both Ultra-Boy and Superboy find out that they are really costumed super-heroes when they both scan each other with their x-ray visions and see their costumes under each other. When Pete is trapped in the Smallville bank's vault, Ultra-Boy and Superboy arrive to save him. However, when Superboy's x-ray vision is unable to peer into the workings of the lead based vault door, Ultra-Boy is able to do so because his vision does not have the same limitation.

With Pete Ross freed, Ultra-Boy reveals to Superboy his purpose for trying to learn Superboy's identity: That he's really an alien from the 30th Century, and that his reward for learning Superboy's identity would be membership in the Legion of Super-Heroes. With his mission a success Ultra-Boy returns to the future with Marla and bids farewell to Superboy and Pete.