The neighborhood is currently being held in thrall by an elusive female burglar known only as "Madame X." Through a series of typical I Love Lucy misunderstandings, Lucy (Lucille Ball) and Ethel (Vivian Vance) each suspect the other of being Madame X, and accordingly go to great lengths to catch one another "in the act." Things come to a hilarious head when the real Madame X shows up just as both Lucy and Ethel prepare for their last great pounce. ~ Rovi