Hideki Motosuwa, a diligent country boy, is striving to enter college. With limited funds, he can hardly cover his expenses, much less indulge in the latest trend: Persocoms, personal computers designed to resemble humans. One night, on his way home, he stumbles upon a discarded Persocom. He takes her home and manages to activate her, but she appears to be faulty, only able to utter the word "Chii," which he adopts as her name. Differing from other Persocoms, Chii is unable to download data to her hard drive, prompting Hideki to educate her about the world in a traditional manner, all while preparing for his college entrance exams.
Together with his friends, Hideki seeks to solve the enigma of Chii, who might be a "Chobit," a mythical type of Persocom rumored to possess genuine human emotions, thoughts, and affection for their owner. The question remains: Is a romantic relationship possible between a Persocom and a human?