"My Sister, Benedict Arnold" seems to be one of those episodes The Brady Bunch fans remember fondly. While the character focus is on the rivalry between Greg and Marcia, there is still ample focus on the younger kids, who get plenty of time in the spotlight in the school carnival subplot.
In the opening scene, Greg comes home, clearly upset and annoyed over a classmate who beat him out for the final spot in the regular varsity rotation of the basketball team. To deliver a Double Whammy, this same young man beat him in an election for class president. He goes on and on and on and on ... and on and on about how this guy makes phony promises that he supposedly knows he can't keep, butters up the coach but then goofs off behind his back, is a smooth talker to the girls ... just this all-around phony. The classmate's name that will live in infamy: Warren Mullaney.
Meanwhile, Marcia comes home starry-eyed. A high school boy (a sophomore, mind you, and a classmate of Greg's) has asked her out on a date. He's so cute and dreamy, a gaa-gaaed Marcia proclaims to Jan, and that as her right-of-passage she's going to accept what is sure to be a dream date.
We are talking about the same boy, right? Yep, the infamous Warren Mullaney.
Greg lets off some steam to his father, but even when Mike tells him that he'll probably get over his disappointments and that its probably just Sour Grapes, the mere mention of Warren's name is enough to upset Greg, to the point where he can't even think straight. He even gives a bad review of him when Marcia comes to ask him what he's like ("He's at the top of my crumb list! Matter o' fact, he's at the bottom of my crumb list and every crumb in between!" Greg fumes). Greg lets it fester in him ... even after Marcia and Warren realize they have no chemistry; indeed, Marcia says that Warren was very nice, but they just didn't have what it took to start a relationship. They mutually decide to break it off after one date. Marcia goes to tell Greg this, but before Marcia can get a word in edgewise, Greg tells her that she will not see Warren again, or else he'll make trouble for her.
Marcia is really pissed, and the argument continues at breakfast, escalating when Marcia tells Greg that she intends to bring Warren over, just to prove she isn't going to let Greg push her around. Mike and Carol put a halt to the argument, sending Marcia off to school before they pull Greg aside to reprimand him on his attitude and that he has no right to say who his siblings bring over to the house, so long as they as parents approve. Then, Greg conveniently remembers something and asks whether the same rule applies to Marcia. Carol does an, "Of course," which to Greg (wrongly) implies as permission to annoy Marcia by bringing over someone she isn't speaking to.
That person is Kathy Lawrence, the girl who beat out Marcia for head cheerleader on the Filmore Junior High eighth-grade cheerleading team. Greg decides that what he's suggested was a study date is instead a "see if you can get Marcia even more pissed" date. To which an unwitting Kathy agrees to do ... with her famous rendition of the Filmore Junior High cheer:
- ''F-F-F-I-L!"L-L-M-O!"O-O-O-R-E!"Filmore Junior High!"(Add in the "Yay, team, yah!" after the final of three sayings, said rendition the most enthusiastic at Greg's suggestion.)
Eventually, Marcia calls Greg into the kitchen to talk things over, and things escalate into a very angry argument, each accusing each other of being a backstabber and getting revenge.
Just then, Mike and Carol come home and put a very quick, decisive stop to it. The folks say both Greg and Marcia are equally guilty of the Cycle of Revenge and order them to stop it immediately, and then to go apologize to their dates. Except that Warren and Kathy have already left ... to start a relationship of their own!
The subplot doesn't have that much to do with the main story, but it is a nice way to spotlight the younger kids as they prepare for Clinton Avenue Elementary School's annual carnival. The main focus is on The Brady Booth, a dunk tank where students may, for a quarter, attempt to dunk the principal, teachers and others. During the course of the show, Bobby and Alice both take a bath, but only after pulling the target themselves (Bobby, when Peter was called in to do his homework before he could finish his throws; Alice after accidentally pulling the target to untangle a towel from the arm).
Tropes present in this episode (YMMV can be seen here):
- The Ace: Warren Mullaney, to Greg.
- Always Someone Better: Warren Mullaney, whom Greg considers a phony instead of a more gifted classmate he can learn from.
- Backstabbing the Alpha Bitch: Although here, it's all because Greg is irritated with Marcia (for dating someone he considers his rival) than her being a bitch. He does the backstabbing by asking one of Marcia's ex-friends, Kathy Lawrence, out.
- Cycle of Revenge: Although Mike and Carol put a stop to their eldest two children's backstabbing cycle very quickly and decisively.
- Dispense with the Pleasantries: When Mike and Carol walk in on Greg and Marcia quarreling, the latter two realize that their parents have walked in and try to greet them. The less-than-pleased Brady parents cut right to the chase and order them both to the den for further questioning.
- Double Date: Since both Greg and Marcia had each other's dates over, it would qualify. While Mike and Carol are scolding their children, Warren and Kathy whom have been asked to stand by so that the soon-to-be-humbled Greg and Marcia can apologize hit it off very quickly ... and had the chemistry that their relationships with their Brady dates lacked.
- Feud Episode: Greg and Marcia when they date each other's respective (perceived) rivals.
- High School Hustler and Social Engineer: How Greg views Warren — someone who lies to his friends to win a class election, a smooth talker to the girls, a slick talker to his teachers and coaches and so on.
- Late for School: The excuse Greg tries to give when he decides to hurry out of the house after his argument with Marcia. Doesn't work Greg (who likely knew he was in the wrong anyway) is pulled aside anyway and reminded that he has no right to screen his sister's dates as he had been doing.
- School Carnival: The subplot of the episode. Watch for "The Brady Booth," the dunk tank whose name is a clever play on the show's name.
- Sour Grapes: What Greg is clearly fuming in the opening acts when he loses the final varsity spot and the class president election to a guy he considers his rival — and a phony who goofs off behind his teachers' backs to boot ... Warren Mullaney. He fails to consider the possibility that Warren was simply better and more skilled than him at basketball (Greg had suggested that Warren had the coach in his back pocket) and won a fair election, instead accusing him of "making promises he didn't keep."
- Triple Whammy: Greg might have taken being picked over for the varsity basketball team or losing the class presidency to Warren if only one of those happened, or even if it had been to two different guys connected with said events. But then we'd have no plot or for Greg to decide he hated Warren with a passion, or consider him a phony. Those two events are just the Double Whammy the Triple Whammy comes when Marcia tells Greg that she has been asked out by Warren.