In a future where personal computers have evolved into Persocoms, mobile devices that resemble human beings, Hideki Motosuwa, a prep‑school student, longs to own one but cannot afford it. One day he finds a discarded Persocom and decides to keep it. When he turns it on, the only thing it says is “Chii,” so he names her that. As time passes, it becomes clear that Chii is more than an ordinary Persocom; her superior performance suggests she might be a Chobit, an advanced type of Persocom rumored to possess independent thought.