The Legion travels to the past, to Smallville, to escape Mordru the Merciless. Mordru is a feared magician from Zerox that has incredible powers. Once defeated by the Legion years ago and trapped in an airless vault, Mordru somehow escaped.
While in Smallville, the Legionnaires create secret identities while trying to plan a way to defeat Mordru. However, Mordru has taken control of several citizens of Smallville to look out for any Legion activity. Just when they decide to fight Mordru, Lana Lang (one of the people Mordru has controlled) sees the Legion and Mordru comes to Smallville to fight.