1x21 - Superboy

Clark witnesses the kidnapping of Professor Craig Lipcott a famous nuclear scientist. As Superboy, he follows the kidnappers to a rooftop and sees them enter a strange ship just before he is attacked by a powerful ray that leaves him disoriented. When he looks up the ship is gone. Lipcott awakens inside the ship, which is actually a time machine, with two mutant men and a normal woman, Vora. The mutants want plutoinum. They reveal that they are from the 24th century and that they need plutonium to fight their enemies since no more exists in their time. TJ and Clark begin to investigate the kidnapping. TJ is taken by the mutant time travelers. Vora is sent to find Superboy so he can help them break into the installation where the plutonium is stored. Vora reveals to Superboy that she herself is a mutant in her society since everyone else has been mutated by fallout over the years. Superboy agrees to help in order to save TJ and Lipcott. Superboy gets the plutonium and flees with it.