Chi est un chaton doux, espiègle et jamais à cours d'énergie. Après avoir bu du bon lait apporté par Yohei, Chi se prélasse dans la douceur de sa maison. Excitée à l'idée de faire de nouvelles découvertes, elle part à l'aventure et croise alors Yohei, les mains pleines de balles en caoutchouc. Quelle joie, les balles rebondissent partout. Chi et Yohei ne pourraient pas être plus heureux.

Le soleil vient de se lever, et une belle journée s'annonce. Chi revient de promenade. Alors qu'elle entre dans la maison, les pattes toutes sales, elle découvre un beau tapis tout neuf. Maman et Yohei sont pris au dépourvu, Chi court déjà dessus. Chi est encore un chaton et ne comprend pas encore ce qu'on lui dit. Une nouvelle journée animée débute pour toute la famille !

Noiraud décide de donner des cours à Chi. Elle apprend à se cacher, à sauter de très haut, et plus encore. Il lui apprend tout ce qu'il faut savoir pour qu'elle puisse se protéger face aux dangers du monde extérieur. Tenir tête à un gros chien, escalader un mur avec agilité, éviter une voiture... Elle fait de son mieux pour y arriver. Un troisième épisode, toujours empli de douceur.

Un odeur douce et sucrée traverse la maison… ce sont les pancakes de Yohei! Chi découvre pour la première fois, leur goût délicieux. C'est si agréable. C'est décidé, Chi part à la découverte des saveurs : le café de papa, un grand chou bien frais, de la nourriture pour chats qui croustille... Et pour le dîner, du fromage fondu partagé avec joie par toute la famille.

C'est la fête d'Halloween. Comme Yohei et tous les enfants du quartier se déguisent, Papa décide aussi d'offrir un adorable costume de lapin à Chi. Le costume enfilé, il essaie de photographier Chi mais les chats détestent qu'on les habillent et Chi le fait savoir. Soudain, les lumières s'éteignent suite à une panne de courant. La panne résolue, Papa offre alors un très beau cadeau à Chi.

Chi a pour habitude de suivre Maman partout. Elle est toujours dans ses jambes et ne la quitte jamais, même lorsqu'elle doit faire le ménage. C'est un peu agaçant pour Maman alors que Papa, lui, est un peu jaloux. Pour capter l'attention de Chi, il décide de la brosser. Chi adore se faire brosser et ils profitent, tous deux, de ce moment de complicité.

The newspaper Chi was playing on is replaced with a litter box.

Chi believes she understands why people say a certain word to her a lot.

Chi remembers her mother and tries to go out and find her.

Asleep after a long day, Chi has dreams and nightmares about her past.

The Yamada family believes they've found a new owner for Chi, but Chi isn't so sure.

The Yamada family decides to keep Chi as they can't give her to anyone.

Yohei is told to clear up some bouncy balls, but Chi knocks them down.

Mr. Yamada worries that Chi doesn't have any toys.

Chi has a bundle of new toys, but doesn't know what to do with them.

Mr. Yamada is trying to work. Chi has other ideas.

After Mrs. Yamada frightens her, Chi dashes out of the apartment.

Chi discovers the world outside the apartment.

While Yohei searches for her outside, Chi has fun discovering the local park.

The park becomes lonely and scary at night.

It's time for Chi's health checkup, but how to smuggle her out?

The landlady nearly spots Chi, but Yohei's quick thinking saves the day.

Chi's first medical check-up is a traumatic experience.

Chi is afraid that Mr. Yamada wants to take her for another check-up, and won't come near him.

Chi wants to scratch something. Unfortunately, her objects of choice are very expensive.

Mr. Yamada gets a new pair of jeans, but Chi prefers the old ones.

The Yamadas buy Chi a board to scratch, but she isn't sure what it's meant to do.

Mr. Yamada undertakes the dangerous mission of clipping Chi's claws.

Mrs. Yamada needs to go shopping, but Chi wants to come along for the ride.

Things are inexplicably boring around Chi's house, and dinner is unusually large... a conspiracy is afoot to help her become independent.

It's Chi's first day home alone, but Mr. Yamada is worried about her.

Chi learns that an apartment without humans in it isn't as delightful as it seemed.

Mrs. Yamada needs to take out the trash, but Chi clings to the bag. Mrs. Yamada distracts Chi with a ball, but while Mrs. Yamada is out, Chi climbs up to the window and is almost seen.

Mrs. Yamada takes away the books and boxes so Chi can't climb to the window. However, when Chi jumps, she's just a few inches short of reaching the windowsill.

Chi is able to jump up to the windowsill, so Mrs. Yamada closes the door to Mr. Yamada's workroom. This angers Chi. Mr. Yamada buys a stuffed animal.

When talking with some neighbors outside, Mrs. Yamada thinks they've seen Chi in the window. However, it was the stuffed animal that Mr. Yamada bought. So, they buy more stuffed animals to put on the windowsill so Chi blends in.

Chi searches for a delicious snack, then later eats Yohei's pancakes and finds them delicious.

Chi thinks that everything Yohei plays with is prey. So, Yohei tries to find things Chi will not like, but only makes Chi happier and then she rubs against Yohei's hand.

Chi becomes suspicious of how much fun Yohei and Dad are having fun in the bath, so she goes in to see what they are doing. After Yohei pours toys in the tub, Chi looks over them and wants to play but unfortunately falls into the tub.

Yohei and Chi are both annoying each other with their bad sleeping postures, then later sleep comfortably together.

While Chi and Yohei are playing in the sand box, a large black cat appears from behind the bushes. They run inside, but the black cat walks into their home.

The black cat appears again in the Yamada house and eats Chi's dinner while the others are away.

After eating Chi's dinner, the black cat picks her up and walks over to take her chew toy and Chi tries to protect it. Then the black cat decides to groom Chi's back and so Chi realizes the cat isn't as mean as it looks. And leaves once again into the bushes.

Everyone tells Dad about the large black cat at dinner.

Chi wants to play with everyone but everyone is too busy. Once they all come together to play with her, she dislikes the attention and walks away.

Chi tries to grab the Yamada family's attention when they sit together and discuss how they should go to Kyoto after seeing a postcard from Grandma.

Chi is housesitting again and gets her tail stuck to a roll of tape.

Chi tries to remove the tape off her tail, and in the process she wrecks Dad's room.

Chi follows the black cat and talks to it.

The black cat hides Chi from a dog, then later tells her that she's a cat.

Chi hides from a dog, then can't find her way home.

Chi returns home by taking advice from the big black cat by looking at the sky.

Dad tries to take Chi to the vet, so she runs outside. The land lady almost sees her until the black cat jumps out of a window saving the Yamada family and Chi.

Dad brings out the basket to take Chi to the vet, but Chi knows the basket means she's going to the vet so she runs away every time they try to put her in there... until she traps herself and Yohei catches her.

Chi goes to the vet after Yohei captures her. When she returns home the black cat tells her not to trust humans, but Chi doesn't know what trust is.

Chi returns home just to eat, but gets a treat of Tuna of tells the Yamada family to be her comrades.

There's a storm coming to the Yamada home.

When Yohei goes outside to get his toy truck from being swept by the storm, Chi is left outside.

Dad finds Chi outside the window in the storm.

The power goes out in the Yamada house, so Dad brings out the flashlight and Chi chases it, then Mom and Yohei all play with Chi with the flashlight in the dark.

Yohei becomes ill, but Chi still wants to play. So she stands over him while he sleeps, then eventually cuddles and sleeps next to him.

Mom becomes sick so Yohei tries to help her.

After Yohei and Mom are no longer ill, Dad catches a cold.

Dad is trying to get better but all Chi wants to do is play.

Yohei and Dad are out, so Mom catches up on some housework and accidentally scares Chi while cleaning the floors, so she bribes her with snacks.

While getting ready to go out Mrs. Yamada loses her ring, Chi then helps her find her ring

Chi looks for a place to nap, then ends up kneading and falling asleep on Mrs. Yamada.

Chi gets a taste of milk and ends up wanting more, so she tries to think of a way to get more, but ends up eventually forgetting about the milk while playing with a plastic bag.

The Yamadas decide to make a meal for Chi, but when they give it to her they forget to let the meal cool off.

Chi finds where her food is stored and ends up eating all she wants. Mr. and Mrs. Yamada then worry if she's sick.

While the Yamadas eat dinner they end up giving bits of their food to Chi which makes her believe all food on the table is yummy. To make her stop begging for their food they put her cat food dish on the table.

Chi's shedding season has started leaving fur all over the house. Then a woman from the neighborhood stops by, so the Yamadas have to hide Chi and all her fur as well!

Chi's shedding so Mr. Yamada decides to buy a brush for Chi. Chi ignores Mr. Yamada's attempt to brush her a first but once he starts she really likes being combed!

Chi really likes being brushed so she ends up following Mr. Yamada everywhere asking to be brushed. Chi ends up getting brushed so often that Mr. Yamada's arm starts to get tired.

After being brushed Chi leaves fur on the brush which Yohei then collects until he has enough for a large ball. When Mr. Yamada discovers what Yohei has been doing the family talks about it until Chi grabs the ball of fur and starts to play with it sending fur flying everywhere

Chi and Yohei both want to play but seem to have different definitions of fun, Mrs. Yamada then tells them to clean up so they can have snacks.

Chi and Yohei decide to play hide-and-seek.

Playing hide-and-seek with Yohei, Chi hides in a dresser drawer, but when Yohei goes to have a snack he forgets about finding Chi.

Yohei remembers the game of hide-and-seek and the Yamadas start looking for Chi, while Chi wakes up and tries to escape the drawer.

Chi learns how to open the screen door when the black bear cat shows her how, Chi also learns How to mark her territory and hunt prey.

Chi continues to follow the black bear cat, then chases pigeons. No matter what Chi does shes can't catch any pigeons

Chi chases pigeons while the black bear cat watches but she can't catch any. After being laughed at by a pigeons, the black bear cat tells Chi to sneak up on the pigeons using the bushes.

While Chi and the black bear cat head home, they spot another cat urinating on a car. Black bear cat, furious because the car is part of his territory, chases the other cat away. Unfortunately, the car's owner sees the urine on his bumper and blames the black bear cat. Chi and the black bear cat are forced to flee to Chi's house.

Chi opens the screen door and tries to go outside when Yohei stops her. As the Yamadas try to figure out why the screen door was left opens they then watch as Chi opens the screen door again and tries to escape, again.

The landlady drops by for a visit so the Yamadas must hide Chi from her.

With the landlady visiting, Youkei and Chi hide in the bathroom but because Chi wants to play, the Yamadas have to try to make up excuses so she doesn't find Chi.

Mr. and Mrs. Yamada discuss what they should do with Chi but Chi keeps distracting them by wanting to play.

Mr. Yamada wants to take a picture of Chi but every time he is about to take the picture Chi moves, so when they finally get her to look at the camera, Chi really doesn't like the flash.

Juri comes over for a visit but Chi doesn't seem to happy about her coming, deciding she can't let her guard down around Juri.

Juri's brought a Crab with her from her home and Chi's interested in the live crab; Juri decides to pet Chi but is a little too rough.

Chi's taken a liking to Juri and they start playing, leaving Yohei feeling left out.

Chi follows the black bear cat outside; the black bear cat and Chi try to steal food but end up being seen by the landlady and another resident.

Chi and the black bear cat escape from the landlady and are chased outside, meanwhile Yohei and Mrs. Yamada look for Chi and end up seeing Chi and the black bear cat's escape.

Chi and the black bear cat escape from the landlady by taking refuge in the black bear cat's home, But the landlady finds out where the black bear cat is staying so they have to escape out the window. Yohei and Mrs. Yamada continue to follow Chi's trail.

Chi must jump out the window to the roof of another building but is too scared to do so, so the black bear cat tells her to "smile and look forward" giving her the courage to jump. Then while Chi and the black bear cat are getting down from the roof using a tree, Yohei seeing the black bear cat helping Chi.

The Yamadas discuss how Chi was seen by the landlady, while Chi climbs the curtains and ends up stuck and tangled.

The landlady sends out a notice stating that pets are forbidden in the apartments but Chi wants to go outside and visit the black bear cat.

Chi is sad that she's not allowed to go outside and play with the black bear cat so Chi waits by the door all day wishing to go out, while Mr. and Mrs. Yamada discuss whats best for Chi.

Chi is sad and staring at the Moon wanting to go outside when the black bear cat appears at the door, Chi then begs Yohei to open the door so that Chi can play with the black bear cat and Yohei gives in and opens the door making Chi happy.

The black bear cat brings Chi a "souvenir" and plays with her. Then as the black bear cat leaves Chi asks for the black bear cat to play with her again later and the black bear cat agrees, then leaves.

The Yamadas and Chi watch as the black bear cat and his family pack up and move and as the black bear cat leaves Chi doesn't realize the black bear cat is moving.

The black bear cat moves away so Chi is sad.

Chi discovers that the black bear cat is still there, she just can't see him.