Mototsuwa Hideki is a ronin who need to go to a summer school in Tokyo to pass the coming entrance exam. When he went to Tokyo, he was amazed by the persocons, human-shaped computers. He was dreaming to get one but he doesn't have any money to buy one for himself.

One night, he found a persocon in the trash area and picked it up thinking that no one needs it anymore and took it home with him. And when he turned it on, the persocon started moving but all it could say was the word "chii" so he named her Chii.

This was the start of their funny, embarrasing, and confusing story and secrets about Chii's personal story.

Chii - a very special persocon with a mysterious past that Hideki found on his first day in Tokyo. She is the on rumored to be a Chobits, a very powerful persocon. The story revolves around the two and tries to help each other in everything.

Shinbo Hirobu - A close friend of Hideki and a classmate. Always helps on Hideki's problem with Chii. His persocon is Sumomo, a mobile type of persocon. Has his share of secrets too..

Kokubunji Minoru - a very intelligent person and knows a lot about persocons. All his persocons are personally made by him and he is the owner of Yuzuki.