2x1 - Lois & Clark: The New Adventures of Superman

Luthor's ex-wife, Arianna, comes to Metropolis and creates an exact, but evil copy of Lois. The real Lois, with Clark, begins to investigate who's behind this creation. She discovers that Lex was already married when he tried to marry her. Arianna tries to kill Superman, because she believes he is responsible for Lex Luthor's death.