Having invented a "forget gas" in the previous episode, eccentric scientist Professor Pepperwinkle (Phillips Tead) is back with a new creation, a robot named Mr. MacTavish. Unfortunately, the main power source for the robot is Kryptonite, which of course is lethal to the otherwise invulnerable Superman (George Reeves). A clever crook named Duke (John Vivyan) decides to capitalize on Superman's weakness by kidnapping Lois Lane (Noel Neill) and luring the Man of Steel into a sealed room where the likewise "abducted" Mr. McTavish is waiting to wreak his unwitting havoc. ~ Hal Erickson, Rovi