Jan submits an entry to an essay-writing contest and her teacher, Mrs Watson, is impressed with the title: What America Means to Me. Mrs Watson goes on to say that Jan has improved her work, which she expects from a Brady, and Marcia was one of her best students. Jan has heard that one from Mrs Watson already. Mrs Watson says if Jan tries harder, she can do as well as Marcia. Being compared unfavorably to Marcia upsets Jan and she refuses to walk home with Marcia as they had agreed.
Jan arrives home in a bad mood, takes one look at Marcia's awards, and puts them in the closet. Marcia gets a surprise when she arrives home and starts looking for her awards. Eventually she concludes it is another prank from the boys and this leads to one big argument, which Mike arrives home to. The boys protest their innocence, and then Cindy brings down the awards, which she found in the closet. But they still have to solve the mystery of how the awards got in the closet, and the process of elimination leaves Jan.
While Marcia is putting her awards back, Jan admits what she did, and an argument breaks out. The parents hear it and this leads to them having a serious talk with Jan. Jan complains about how everybody at school praises Marcia for her achievements, and the catchphrase "Marcia, Marcia, Marcia!" is born. Jan tells her parents that she is sick of being in the shadow of the sister who always seems to be successful. Her mood is not improved when Marcia bursts in with the news that she has been made editor of the school paper. The parents tell Jan that if she feels she is in Marcia's shadow, she should do something about it by finding her own strengths and develop them.
Jan tries her hand at pompom girl, as this is something Marcia has never done (actually, Marcia did try out for it). At home she starts practicing hard, and Carol and Alice try to help, but there are warning signs that she is good, but not good enough. Sure enough, she fails the audition. Jan is shattered and Marcia, who was watching, tells her parents the sad news.
However, they are surprised when Jan comes home in great excitement. Her essay won first prize in the contest with 98 points, the highest score anybody ever got in that contest. At assembly on Monday she will be presented with a certificate in the Honor Society and be a celebrity in the school paper. Best of all, Jan has finally done it - outdo Marcia.
Then, when Jan goes over her score, she discovers a mistake was made. Her score is actually 93, and the true winner is Nora Coombes with 95 points. Jan has to choose between being honest and disappointing her family who thought she was a winner. She says nothing for now, but is not comfortable with all the praise and celebrations her family are giving her. In the end she tells Mrs Watson the truth at the assembly. Mrs Watson declares the error in the marking and Nora Coombes is the winner. She adds that she wishes she had a special award for Jan for giving a whole new meaning to the words 'Honor Society', but her parents (who are watching), must be very proud of Jan for her honesty, and Jan should be an example to them all. Afterwards, the parents tell Jan that sometimes when we lose, we win, and they are proud of what Jan did.
At home, Marcia tells Jan that she caused a sensation and her class is buzzing about it. Then Cindy comes in looking sour and angry at Jan. She says they changed her room in school and she got one of Jan's old teachers who heard about what Jan did. Now all Cindy hears is what a great sister she has: "Jan, Jan, Jan!" Her older siblings give her the same advice the parents gave Cindy, but Cindy says that will not be easy as she is good at many different things.
Alice is happier because the cheers she learned while helping Jan with pompom practice have made her housework much easier.