Grampu takes Oobi, Uma and Kako camping.
Oobi and Uma visit the playground, where Uma learns how to be careful on a swing.
Uma refuses to take a bath after playing in the mud with Oobi and Kako. Grampu chases her through the house and tries to convince her to wash up. Uma eventually climbs into the bathtub and has fun by singing a song about bathtime. Grampu is relieved that Uma is clean, but he is less than thrilled to clean up the dirty bathroom.
Oobi and Uma sign up for dance lessons. Their instructor, Tulla, teaches them the importance of practicing. After they master a synchronized dance routine, Tulla throws a disco dance party for them. Grampu feels the beat and joins in.
Oobi is excited when Kako asks him to watch his puppy while he's out. Grampu helps Oobi realize that pets are a big responsibility and need to be walked, fed, and washed. After learning how to take care of dogs, Oobi finally gets to play with the puppy.
Oobi, Kako, and Grampu throw Uma a big surprise party for her birthday. They play games, give her presents, and dance in a conga line. After a while, Uma feels overwhelmed when the party becomes more about the games and less about her. She retreats to her room, and Oobi learns that she would prefer a small party. The others decide to give her one by bringing in one small gift and a tiny birthday cupcake.
Oobi and Grampu try to get Uma to try asparagus. After their attempts fail, Oobi is able to trick her into tasting it, and she ends up loving it.
Oobi wakes up with a wild patch of hair on his head. He tries hiding and styling it, but nothing satisfies him. In the end, he and Grampu go to the barbershop. Oobi is able to overcome his fear of getting a haircut and happily returns to his old hairless self.
The kids create their own holiday to celebrate Grampu and each give him a gift. Oobi makes a statue of Grampu out of clay, Kako makes food, and Uma sings a short song. The statue looks nothing like Grampu and the food is disgusting, but Grampu has a great time and enjoys Uma's song.
The kids are a little too eager to help Grampu make pizza, and end up doing everything the wrong way. They throw the dough on top of Grampu and smash tomatoes instead of using tomato sauce. Luckily, the pizza turns out okay, but they forget to leave a slice for Grampu. They then make him another to make it up to him.
Uma wants to be a part of Oobi and Kako's puppet show. They let her help make the costumes, but when she accidentally glues the boys and their props together, they insist that she should just watch. They soon regret their decision when they find out that they need Uma's help to open the curtain when their costumes prevent them from opening it themselves. Oobi asks her to come back, and she becomes a star of the show.
Oobi reluctantly lets Uma play with his favorite model car while he helps Grampu with the sink. When she accidentally breaks one of the wheels off, she tries to repair it herself and ends up damaging more of it with each touch. Oobi gets mad. Grampu explains that accidents can sometimes happen and fixes the car with the kids' help.
Grampu introduces the kids to his favorite pastime, gardening. He teaches them how flowers grow and gives them a seed to plant. They find it boring waiting for their plant to grow, but their patience pays off when it becomes a small sprout.
Grampu falls in love with Oobi's piano teacher, Inka, when she comes to visit. She teaches Oobi how to play a scale and even lets Grampu show off his piano skills.
Uma takes Oobi and Kako's farm animal game too far and won't stop pretending that she is a chicken. She wears a chicken costume, pecks at her food, and tries to lay an egg. However, when she meets an actual chicken, she decides that it is more fun to be herself.
Kako invites Oobi to a sleepover. Uma misses Oobi terribly and is disappointed that she wasn't invited. Grampu does his best to make Uma feel better, but the only thing that works is a phone call and a lullaby from Oobi.
Kako becomes frustrated with tee-ball and refuses to play. After Oobi learns the basics of Kako's hand-clapping game, Oobi teaches Kako the fundamentals of tee-ball. Kako gets a hit and Uma is revealed to be a tee-ball natural.
Oobi and Kako build forts out of blocks and get into a heated argument over whose is better. They try to one-up each other by bribing Uma, Grampu, and even the viewers to join their respective forts. They eventually make up and combine their forts after agreeing that arguments are no fun.
Grampu takes Oobi and Kako to the petting zoo. The boys are afraid of the horse at first, but they overcome their fear after joining Grampu for a horseback ride and pretending to be cowboys.
A day at the park with Grampu becomes very special for Oobi when he meets a five-year-old girl named Frieda who looks very different from him. Oobi learns that differences are good and new friends come in many shapes and sizes.
Oobi and Kako try to make Uma feel better when she comes down with a fever. They make her a card filled with things she likes and perform a "get-better" dance, but what she really needs is some rest. They decide to sing her a lullaby, and Uma is healthy again after getting some sleep.
Kako gets jealous when Oobi becomes obsessed with his new pet turtle and forgets about a playdate they planned. Oobi makes every game about the turtle. Oobi realizes how upset Kako is and makes amends with him.
The kids decide to make art together after seeing Grampu's painting. Kako paints a colorful pattern, Uma creates a circle-themed piece, and Oobi makes a collage.
After the rain spoils their plans, Oobi and Kako reluctantly join Uma to find a rainbow. They cheer up after catching raindrops and splashing in puddles before finally finding a rainbow.
Oobi, Uma, and Kako are disappointed when they cannot visit the circus because it is too far away. They decide to use their imaginations to create their own pretend circus.
The kids form their own band and try to find makeshift instruments. Kako blows into a bottle, Uma bangs on a pot, and Oobi claps with Grampu.