On the way home from running errands, Mary hits a BMW, breaking the tail light. From the persuasion of Rose, she decides to leave a note on the car. The next day, after no one has arrived to see the car, Mary wants to remove her note. However, another car comes by and nearly totals it, but then drives away. Before Mary can get to the car and remove her note, the owner comes out of an apartment and sees her note. Sandra tells Mary that she needs to use her "femininity" to get out of paying for the total damages. Mary says that she can't do that, so Sandra poses as Mary when the owner comes by to talk to Mary about the damages. Everything goes well until Lester comes home and their lie unfolds. Everything gets straightened out between Mary, Lester, and the car owner (Marvin), ending with a date for Sandra and a new friend for the Jenkins. Meanwhile, Mary tells Brenda that she cannot go skating with Calvin because she lied.

When Mary's brother Lewis comes to town on business, she decides to set him up on a date with Rose. The next day when Rose won't give Mary any details about the date, they get in to an argument where Rose finally admits that she thinks Mary's brother is "self-centered" and "egotistical". They stop speaking. Meanwhile, Lewis asks Sandra out on a date, and Mary fears that Sandra may be her future sister-in-law.

For an assignment that requires her to write about her "Most Interesting Relative", Brenda asks her parents for help. Lester suggests his aunt Lucy who was a woman brakeman. After Mary hears about Sandra's supposed relative who was a Moroccan prince, she searches through an old trunk to find information about an interesting relative of hers. What she finds is that she had an uncle, Corporal Mortecai Hurley, who was in the Civil War's 54th Infantry. She persuades Brenda to re-write her paper on Mortecai.

When Mary tries to convince the landlord to order her a new refrigerator, he refuses. Mary then agrees to loan Sandra her apartment for a extravagant party if Sandra will "persuade" the landlord to get Mary a new refrigerator.

News of the breakup of her neighbors' marriage has Mary worried that the same thing could happen to her and Lester. Mary plans an evening of romance for her and Lester. Lester buys flowers (at Mary's suggestion) and they try to force romance by going out to eat, dimming the lights, and playing romantic music. But they realize that they only think that works is by letting it happen naturally and reminiscing about the past. Meanwhile, Sandra has to babysit her 6-year-old niece Susie while her sister Harriet and her husband visits his sick mother. She solicits Mary's advice on what to feed her and how to get her to fall asleep.