Superman interrupts a robbery at Lex Luthor's new Natural History museum. He has an easy time of it, even toying with the robbers a bit — until he suddenly gets weak and keels over, allowing the robbers to escape. Luthor, reviewing the security tapes, notices that it happened when Superman stood in front of a display containing an odd green rock
. He sees an opportunity to get the hero out of his way, permanently.
This episode provides examples of the following tropes:
- Achilles' Heel: This is the first time that Kryptonite appears in the series, and is promptly identified as Superman's only weak point.
- Bodyguard Babes: Lex Luthor is shown to have one of those.
- Chekhov's Skill: Lois being able to make baskets with paper wads. It comes in handy later to neutralize the Kryptonite.
- The End... Or Is It?: In the next-to-last scene, Supes throws the lead-encased chunk of Kryptonite into space. In the very last scene, a Luthor-sponsored team searches for more of the green rocks, and the camera pans to show one lying nearby.
- Tyrannosaurus rex: Luthor uses a mechanical replica with a piece of Kryptonite in its mouth to attack Superman.