Hideki has moved to the city from the country to enrol in Prep School in order to pass the college entrance exam. In the city, Hideki is amazed by the mobile computer units called Persocoms that almost everyone has. If only they weren't so expensive! Walking one night he comes across a cute persocon just lying in the trash and decides he should do his part for the environment and recycle her as his own.

Hideki wakes up to discover he really now owns a Persocom~! Shinbo comes over and realizes what Hideki was hiding the other night. He tries (stress tries) to help Hideki by seeing if Chii has any DATA or PCN numbers. When he can't find any (After Sumomo has crashed from trying) he sends Hideki and Chii to Minorus house. Minoru too is unsuccesful, but Yuzuki has given info that Chii has DATA just hidden. Minoru talks about a legendary Perscom series called "Chobits." As they go home Minoru gives Hideki some advice about Chii.

Things start to look a little better for Hideki as he tries to teach Chii some words and expressions. Although he’s in need of a job, Hideki gets to start cram school today, and it turns out he’s got a very attractive teacher, Ms. Shimizu. After making the rounds for job hunting, Hideki manages to land a job from a wet accident, meeting another cute girl, Yumi Ohmura, in the process.

Hideki's a decent guy overall and realises it's a bit perverted to have his girl persocom running around the place with no underwear. Unfortunately, inexperienced as Hideki is, buying female undergarments holds a great source of embarrassment for him. Hearing about the dilemma Shinbo offers Sumomo's services as navigator and generally being a source of common sense for Chii, in order for her to go and buy her own underwear. This sounds like a great idea at the time, but causes a seemingly infinite amount of worry during the day at prep school for Hideki.

Hideki's first academic hurdle comes in the form of an impending mock test. This spurs some serious studying, hindered only by the lack of a Japanese-English dictionary. With the help of a visit to the bookstore Hideki gets rather side tracked and decides to teach Chii to read, using a picture book she was seemingly drawn to. With a visit (and some help) from Shinbo Hideki gets back to the books, leaving Chii to finish reading her book by herself. When Hideki finds Chii later she is emitting light and floating in the air! A Check from Shinbo finds nothing wrong with Chii, leaving Hideki with more study and less time, but at least Chii is around to motivate him.

Chii isn't feeling like herself and basically collapses in Hideki's apartment. He gets an adapter from Shinbo but unfortunately can't recharge Chii due to the fact that he never paid his electric bill. He struggles to find a building to recharge Chii but falls when climbing a wall to a building which is open til 2am. Luckily for him Ms. Hibiya saw them froma cab window and allowed Hideki to charge Chii from her place. Shinbo arrives and informs Hideki and Ms. Hibiya of how many watts are being used to recharge Chii. Hideki exclaims that he will pay her back for both the electricity used and his rent even if it kills him.

With Hideki broke, Chii decides that she wants to find a job to get money to give to Hideki. Hideki has little objection, but stipulates that Chii must find a "good job" to work at. Unfortunately for Chii, someone with a very bad job for Chii, finds her while she's out and tells her the job he has on offer is a "very good job."

After Chii's reboot button is pushed, she escapes the 'peep show' room and is jumping around the city disabling all persocoms. She finally exhausts herself and Hideki catches her before she falls off a railing. Chii gets a job at a bakery having a five year anniversary thanks to Hideki. The manager offers Chii a permanent job which she accepts only if Hideki allows it. She trys to give Hideki her payment but he refuses telling her that since she worked and earned it, it belongs to her and for her to buy her favorite things (whatever they may be)

Chii decides to use her money to buy the sequel to the book "A City with No People" and a porno magazine for Hideki, who learns from Shinbo that Persocoms need bathing. Since he doesn't have money to buy bathing software for Chii, he has to teach Chii how to bathe. Hideki asks Minoru for help, and when they meet, Minoru shows him a picture that appears to be Chii. The picture came from an untraceable email. At the public baths, after some awkward, unsuccessful attempts to instruct Chii on how to bathe herself, Hideki eventually finds a way to avoid the task when he meets his landlady, who helps bathe Chii.

Hideki gets a date with Yumi. While he's out, Chii reads the sequel of her book, which awakens a part of her memory. As a result, she meets a mysterious girl who looks exactly like her, named Freya, who seems to know everything about Chii's past that Chii does not.

Hideki is scared of a room in the apartment because of a horror story he heard at Minoru's house when he was asking about the internet through Minoru's custom-made Persocom Yuzuki. He becomes paranoid thinking about the story and, believing that his apartment building is haunted, has several self-induced hallucinations. The apartment number in the story is 104, as 4, or shi. "Shi" is the Japanese word for Four (四) and Death (死), and because of this, the number four is unlucky in Japan. According to the story, a woman who was hoping to rendezvous with her lover was killed in that room. Hideki and Chii along with Shinbo, Minoru and Yuzuki decide to investigate. At the end, Hideki and Chii discover that it is all a misunderstanding.

Yumi's dad loans Hideki his DVD player, and tells him of a DVD sale coming up. Hoping to get some mature videos, Hideki embarrassingly meets Minoru and sis instead, who offer him a fantasy multiplayer Internet game (Brave Quest Online) that persocoms can play too. Hideki thinks this would be fun to play with Chii. But Hideki knows nothing about hooking up to the internet! Fortunately Shimbo helps him out. Now everyone's logged on, except for Chii; she's missing (in the game)! Oh no, what's Hideki going to do now? Blindly run through the game looking for her of course!

Hideki and the entire gang are invited to hang out at Minoru's beach home for the weekend to study and to have a lot of fun. This is Chii's first time at the beach. But with Hideki not knowing how to swim, and with Chii going in the water, what's a guy to do?

On a hot summer night, Ms. Shimizu pays a surprise visit to Hideki and Chii, and wants to STAY OVER(!!) Is Hideki going to have his first night of passion, or is there some other reason?

Hideki discovered that Shinbo and Ms. Shimizu on the street hugging each other. The next day, Shinbo and Ms. Shimizu aren't at class. And then Sumomo is left in Hideki's care! Could something be up with those two? And isn't Ms. Shimizu married?

Hideki's in trouble grade-wise, so Ms. Shimizu advises he prepare for a practice exam. Hideki gets ready for studying, but loses his wallet. Chii tries to help him out by cooking for him.

Ms. Hibiya is cleaning the apartments, and Hideki and Chii offer to help her. When Hideki goes to clean the electronics room, Sumomo accidentally falls onto some wires and gets electrocuted. Ms Hibiya then reveals that she used to build Persocoms, and she repairs Sumomo.

While Chii is on her way to work, she notices the third part of the book series "A City With No People" on the shelf of a bookstore. While she flips through the pages, she is grabbed from behind and is kidnapped. Hideki comes home from prep school and returns to find Chii missing.

Chii is still in the hands of her abductor as Hideki searches for her. After he talks to Mr. Ueda about Chii missing work, they decide to search for Chii together, and Mr. Ueda talks about his marriage to his last Persocom.

Chii is still missing, and Hideki is enlisting as much help as he can to find her. A strange e-mail image gets sent to him and Shinbo from an untraceable email address. It turns out that this is a map for the house of Chii's abductor, Dragonfly, and he is carrying out research to find out what Chii is.

Hideki and Chii help Shinbo move out of the apartment to live with Ms. Shimizu (who is now married to him). Then they arrive at Minoru's house, where he is trying to find information on Chobits. Minoru, who has not been sleeping enough, passes out, and Yuzuki (Minoru's custom-made Persocom) decides to try to hack the Chobits database herself.

Hideki takes Chii to work. There, Chii changes into the wrong uniform. Ueda tells her it's the wrong one, but before she goes to change, Yumi sees her wearing it from outside the shop and runs away crying. As it turns out, Yumi used to work at the store, and that had been her uniform. When Yumi was working for Mr. Ueda, the two had started falling in love, but when Yumi learned about Mr. Ueda's previous marriage to a Persocom, she concluded that he believed Persocoms to be superior to humans, so she quit her job at his bakery and broke off the relationship.