On being given a family tree project Chuckie and Kimi are excited that they only have one piece of homework between them as they are brother and sister. However Kimi discovers her Japanese heritage and decides that she and Chuckie should work on separate projects, because she is studying all of her biological family's side, not her half father's side (Chuckie's dad). At first Chuckie is supportive of his sister, but after she drags the Finster family into a charade for the schools culture festival, which humiliates them, Chuckie feels forsaken and wants his old sister...
When their hip new teacher, Max, assigns the class a family tree project, Chuckie and Kimi realize they can pool their efforts.
On a trip to a mountain resort, Tommy develops his first crush on a girl named Olivia.
Susie gets a singing gig at Slosh Mountain she gives free tickets to the gang. They are thrilled, not so much about the show, but going on the mother of all rides, Whiplash Gorge. Unfortunately Tommy and Dil find out they have to baby-sit their Grandpa Boris after cataract surgery the same day. Boris will be visually impaired for a while so the boys hit Slosh Mountain anyway. But soon after the boys arrive at the park Boris disappears. Tommy and Dil round up their friends to help him find their Grandpa. Will they find him and make it in time to see Susie's concert?
The whole school has caught Yu-Gotta-Go fever, a role playing card game, except Chuckie. When he finally starts playing, it becomes an obsession, and he's hired by Angelica to do her chores in exchange for more cards. He becomes one of the school's elite players, but in the pursuit of an elusive card, he nearly parts with the valuable stamp collection that Chas has passed down to him.
After Stu sells an invention, he tells the kids that he's splurging on a built-in swimming pool. While digging up the yard, the construction crew unearths the Rats' old mechanical Reptar toy. The kids fondly remember it, but decide to throw it away, until, during an electrical storm, they become convinced that they've angered Reptar.
Dil introduces Angelica to the concept of karma after she deviously beats out Susie for a singing gig. When she wakes up with a giant pimple, she becomes convinced that she must change her ways in order for it to disappear before showtime. Ultimately, Angelica comes clean to Susie who takes the stage for her, and to her chagrin, learns that skin outbreaks are a matter of hormones, not fate.
It's soccer season and as per usual, Phil has soccer-on-the-brain. But when Lil casually joins the team, she surprises everyone, including herself, by instantly becoming a super star. At first Phil is excited about having another soccer-head in the family, but when Lil outshines him, he starts to resent her.
Tommy, Chuckie, Phil and Dil decide to put together a boxcar to compete in the upcoming derby against Angelica.
Pangborn and O'Keats lead a life skills project to teach the students the responsibilities of marriage. Chuckie is paired with jock-extraordinaire Fridge, Angelica with Susie, and Harold with Harriet, a female version of him. Each participant learns the need for compromise, cooperation, and communication, and the chaperones learn something about each other as well.
As babies, the Rugrats used to dream about being cowboys, and they get to live out their dream.When the gang is invited to spend a week at a dude ranch, Tommy and his friends try to adapt to country life.
The Rats and their mothers embark on a cross country trip in a beat up R.V. to bring Susie to New York, where she's been selected to perform in a Thanksgiving parade. Generations collide, as the moms want to expose their kids to tourist attractions, but the gang wants to assert their growing independence.
Tommy falls for a pretty Jewish girl he meets in Hebrew school while they are building a house for a homeless family. He tries to impress her by inviting her to Sabbath dinner at his house and telling her that Stu is a rabbi. Will she forgive him when she finds out that he was lying about his father?
As Phil and Lil's birthday approaches, their plan for an epic party is abandoned after Phil sees Lil in her new training bra and has trouble dealing with their impending adolescence. He always considered girls "guys you can't punch," but now is seeing them in a new light. When the twins have separate birthday parties, they try to out prank each other.
Harold wants to ask Angelica to the Mardi Gras party but she only has eyes for Darryl. Susie plays Pygmalion until but this only leads to Harold starting to fall for Susie instead. This change of direction for Harold's emotions drives Angelica crazy and she drops all her feelings for Darryl in order to get Harold back.
Angelica falls for Darryl, but she gets gets too nervous to talk to him whenever he's around. Will her mom hurt her chances with him when she looses her CEO job and decides to become a full-time mom? She might when they get stranded together on a sail boat on the same day as Darryl's rock concert.
Tommy is getting annoyed by Dil's eccentric behavior, and he wants some space from his little brother. When the gang visits the Cirque Extravaganza Day Camp, Dil meets a whole group of kids who are just as eccentric as heÿis who invite him to join their troupe permanently. Will he choose his new circus friends over Tommy?
When the gang sneaks into a PG-13 movie at the mall, Angelica catches them, and she has excellent blackmail fodder. The mall then closes with them locked inside with two bumbling robbers.
After Charlotte has dinner with the Carmichaels, she decides that Angelica could use a bit more discipline, so she has her staying with Susie's family for a week. Tommy then bets the gang that the spoiled princess can handle allÿthe Carmichael family rules for seven days, but can she make it?
Phil falls for the captain of the school soccer team. Meanwhile, Vice-Principal Pangborn asks Dil, Tommy, and Chuckie to hang around with his nephew, who turns out to be irritating and annoying.
Tired of being called perfect and on the edge of boring, Susie tries to go "bad." Her efforts, however, fall short of notice until she completely changes her style. To prove her "badness" Brianna challenges Susie to climb to the top of a dangerous tall old abandoned building to recover some sneakers hanging from the edge of the top floor.
When Chuckie discovers that Kimi is upset, he gets the gang to help him redesign her room. It is then discovered that she is homesick for Japan and her biological father.
When the gang looks for Halloween costumes in the Finster's basement, they find TP+KF carved on the wall. Does this mean that Tommy likes Kimi? If so, Chuckie doesn't like it. Dil goes trick-or-treating the day before in order toÿbeat the rush. The argument between Tommy and Chuckie escalates to where they don't want to be best friends anymore. The gang tries to bring back together just as Chas' new security system to scare away anyone who might want to teepee his house.
When the comic book starring Chuckie's favorite superhero gets canceled, he is too depressed to help Tommy with his science fair project. Armadillo Dave gets canceled and Chuckie breaks down. Tommy has to buy a rat for his project, butÿthe last rat available is a mean one. It scares everybody. Tommy made a simple one lane track for his rat, but needs Chuckie so he can get a good grade on it since Chuckie has done it before. The gang tries to find Chuckie a new hero to worship.
Angelica's teacher is having a baby so she brings in a hot handsome sub teacher that Angelica falls in love with. She tries to "date" him by failing her assignments. Meanwhile, Tommy, Phil, and Chuckie are part of the tennisÿclub run by Pangborn. Chuckie is trying to avoid showering at the boys' locker room, but when he takes the chance, he realizes he has nothing to worry about.
Rachel is moving away and now Tommy is mad. In order to get it off of everyone's mind, he says "Rachel" in class as made-up answers. But when Chuckie starts a gang with Phil and some other of his cousins,ÿTommy tries to sarcastically cry and teams up with Dil during the moment when he's helping Charlotte with the game 'Impatience.'
Kimi leads a petition drive to ban cell phones in school. Angelica hoodwinks Chuckie into helping her keep cell phones in school in her petition drive. Kimi gets busted for wanting a cell phone for Christmas.
With Stu and Didi away at an Invention Convention, Tommy and Dil want to host a viewing party for a "real" alien autopsy video. But when both Grandpa Lou and Grandpa Boris show up to babysit the kids, can theÿgang find a way to watch the "inappropriate" tape before Dil has to give it back?
When the gang's parents feel that they are spending too much time watching TV, they ban it from the house. How will the gang get by without their favorite programs?
Tommy breaks his plans to go the Big Ball Game with Grandpa, so Grandpa decides to take Dil instead. Upon seeing how well Dil and Grandpa are getting along, Tommy worries that he is being replaced as favorite grandson. On their annual fishing trip with Grandpa, Tommy challenges Dil for position as favorite grandson.
All Growed Up is a horror episode of Rugrats that aired on July 21, 2001 during the show's 8th season to celebrate the series' 10th anniversary, and acts as the pilot episode of All Grown Up! Its premise was to focus on what the babies' lives would be like if they were 10 years older. It proved to be popular enough for a spinoff based on it to be made.