Plot summary
Two sisters, Lucille ( Shelley Long ) and Nell ( Mary Gross ) Newtrich (sisters of Gene Newtrich from a previous episode), try to use the red kryptonite Gene gave them to make Superman apathetic so they will be able to steal $20 million. When they shoot him with the red beam though, Superman hugs Lois to protect her resulting in his superpowers being transferred to her. Lois asks Martha's help for a costume, similar to Superman's costume, so people will not recognize her while she will be doing Superman's job under the identity of Ultra Woman.
Jimmy completely falls for Ultra Woman asking Lois to help him get in touch. When Lucille and Nell discover what really happened, they try to transfer Ultra Woman's powers to Lucille while Superman asks for Dr. Klein's (Kenneth Kimmins) help to recreate the weapon Nell used to steal his powers. Lucille and Nell rob a bank and when Ultra Woman and Superman get there, they manage to trick them and Superman gets his powers back sending Lucille and Nell to prison with Nell suggesting Lucille should "pray we don't end up sharing a cell" with Lucille quipping "ooh I'm really scared!".
After her experience as Ultra Woman, Lois realizes how difficult life is for Clark being Superman and trying to save the world all the time and that being in his shoes for a little while has made her love him more. She asks him to marry her and he says "Who's asking? Lois or Ultra Woman?" to which she replies "Who's answering? Clark or Superman?" he says "I'm answering" Lois then says "I'm waiting" and then Clark says "yes".
Credits
Adapted from Wikipedia contributors, Lois & Clark: The New Adventures of Superman season 3. HTML formatting and reference markers removed.