The Bradys set out for a family vacation to the Grand Canyon. However, en route, the family stops in an old ghost town where an old prospector locks them in a jail cell.

After escaping the jail cell, the Brady finally arrive in the Grand Canyon and set up camp. Later, the family is thrown into a panic, when Bobby and Cindy get lost in the canyon while chasing and Indian boy.

Bobby and Cindy find their way back to camp bringing relief to a worried Mike and Carol. However, Bobby and Cindy's wanting to help the Indian boy, Jimmy, in his quest of running away to become an astronaut gets them into more trouble.

Greg buys his first car for $100 from his friend Eddie who made the car into something it's not. Finding that he has been stuck, Greg attempts to do the same thing Eddie did, when he tries to sell the car.

Greg is furious when he discovers Marcia is dating Warren Mulaney, his arch rival who beat him out in a basketball rank. To get revenge, Greg begins dating the woman who beat Marcia out in cheerleading.

Convinced he doesn't have personality, Peter goes all out to try to get one. After imitating celebrities, Peter decides to try a funny personality in which he stocks up on jokes and plans to show his new personality off at a party.

When Marcia gets the lead as Juliet in the school play, she lets it go to her head, which causes her to become unbearable at home and at school and plays as the major reason why she is replaced by her understudy.

A commercial producer discovers the Brady family while they are grocery shopping, one afternoon. He quickly wants them to be in a laundry soap commercial and soon the problem is whether or not to do the commercial since they don't use the product.

Peter begins to secretly eavesdrop in on his siblings private conversations with the help of Mike's tape recorder. This cause sibling rivalry and discord between his brothers and sisters.

Tired of being in Marcia's shadow, Jan is determined to do something that Marcia never did. However, Jan becomes more depressed when she fails to make the pom-pom team and her friend makes the squad. Then she wins first prize in the essay contest and finds out her teacher made a mistake in scoring.

Greg wants to be on the football team, but Carol is against it, fearing that he's going to get hurt. Carol's fears come true when Greg fractures a rib. Meanwhile, Bobby gets a camera.

Marcia makes a promise that she will get Davy Jones to perform at the prom. A promise she quickly learns is going to be very difficult to keep, since trying to get a hold of him is almost impossible.

After taking the wrong bike from school and when her grades begin to slip, Jan learns she may need glasses. Meanwhile, Mike's anniversary gift to Carol is a portrait of the six kids. The trick is getting the kids to the photographer without Carol finding out.

When Bobby and Cindy are not invited to a wedding because they're too young, they set out to do something important. Their goal, break a teeter-totter record.

Bobby becomes extremely self conscious about his height and tries different ways to make himself "big." First he tries stretching himself, and then he decides to improve his mind by memorizing a bunch of worthless facts.

Greg, wanting to make a record, books a recording studio and plans on singing a song with his siblings. However, when Peter's voice begins to change, his hopes of recording his planned song are dashed.

Jan discovers her Aunt Jenny looked exactly like her when she was young. Curious about how she looks now and thinking perhaps that is how she'll turn out to look, Jan asks her for a picture of her now. This causes Jan to become distressed since Jenny, now, doesn't look to attractive.

Bobby bets Greg that he can't do twice as many chin-ups as him. Greg, confident he'll win sits back while Bobby practices. However, Greg is totally unprepared when he looses and Bobby begins taking advantage of the terms of winning.

Peter is popular with his classmates when they find their names in his newspaper column. When he starts getting a poor grade he decides to improve it by flattering his teacher.

Feeling immature because she is the youngest, Cindy feels that she isn't appreciated until she gets a mysterious letter from a secret admirer.

For a joke, Molly Webber, a plain Jane, is nominated for hostess on Banquet Night. This practical joke sends Marcia on a mission to transform Molly into a knockout and she succeeds but discovers she may have succeeded to much when she finds herself running against her.

Carol is in a car accident with a man who agrees to pay the damages. However, a short while later, he changes his mind and Carol finds herself summoned to court with Bobby and Cindy testifying against her.