A gray and white kitten with black stripes wanders away from her mother and siblings one day while enjoying a walk outside with her family. Lost in her surroundings, the kitten struggles to find her family and instead is found by a young boy, Yohei, and his mother. They take the kitten home, but pets are not allowed in their housing complex, they try to find a new home for the kitten. This proves to be difficult, and the family eventually decides to keep the kitten, naming her "Chi".
The black cat appears again in the Yamada house and eats Chi's dinner while the others are away.
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 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.
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 centimeters short of reaching the windowsill.
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.
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.
The Yamadas discuss how Chi was seen by the landlady, while Chi climbs the curtains and ends up stuck and tangled.
Things are inexplicably boring around Chi's house, and dinner is unusually large... a conspiracy is afoot to help her become independent.
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.Watch Now:Amazon
Youhei overhears Mom and Dad talking about sending Chi away and runs away with her. Chi runs from Youhei when he is talking with his parents in the park and chases a bird.
Chi follows the black cat and talks to it.
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 interesred in the live crab, also Juri decides to pet Chi but is a little to rough but in the end Chi thinks it's fun.
Chi's taken a liking to Juri and they start playing, leaving Yohei feeling left out.
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.
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.
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 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.