It was the second part of a three-part story called The Lex Files.
Lois and Clark investigate a deadly assassin resembling a shadow who is murdering several people in connection to Vixen, while Leslie plans to re-establish Lex Luthor's criminal empire.
One by one the people who were involved in Vixen's creation are getting murdered by a man named Hanson who had a terrible accident that turned him into a shadow. He works for Mr. Smith in exchange for an antidote.
Lois and Clark try to solve the mystery while at the same time considering if they can have a their own child together.
Meanwhile Leslie continues to break the two reporters apart while at the same time trying, along with Mr. Smith, to rebuild Luthor's empire.
He sends Lois to a convention and Clark to an exclusive interview while he follows Lois and hits on her causing misunderstandings between the couple.
After finishing his given task, Hanson goes to see Mr. Smith to retrieve the antidote, but he overhears him talking with Leslie saying that there never was one. Furious, he decides to kill the one most closest to Smith; Lois Lane and then kill him afterwards.
Hanson goes to Lois and Clark's house to kill her, but Superman defeats him by exposing him to light, his only weakness which makes him disintegrate into nothing.
Lois and Clark put the pieces together and find out that industrialist Walter O'Neill is behind everything and that his next target is Leslie. Leslie kills O'Neill before Lois and Clark can talk to him claiming that he attacked him first.
After more investigating Lois and Clark see in a file from Jimmy that Lex Luthor had owned the companies where Hanson struck and when he was attacking Lois, he said that he would destroy the son of the man who knew Superman's identity.
They deduce that Leslie was the next target for the shadow killer for the companies that Leslie owned were previously owned by Lex, who in the past had shown Lois his whole empire, so he is Lex's son (Lex had found out Superman's identity before his death in Seconds).
Meanwhile Mr. Smith retrieves a recording of Lex's final communication and he and Leslie listen to it in admiration as it says that Clark Kent is Superman.
- John Shea as Lex Luthor (voice)
- Kenneth Kimmins as Dr. Bernard Klein
- Keith Brunsmann as Troll/Mr. Smith
- Patrick Cassidy as Leslie Luckabee