After enduring four years of high school, Hideki Motosuwa strives to get into the university of his choice by attending cram school in Tokyo. Concurrently, he works daily shifts at a bar to make ends meet, thus missing out on the world's latest invention—human-like computers called Persocoms. Longing for a persocom of his own, Hideki is met with a stroke of luck when he stumbles upon a cute abandoned persocom in a garbage pile.

Upon finding the power button, Hideki finds his newfound robot to be faulty and only capable of uttering the word "Chii"—which Hideki decides to name her after. Chii, however, is no ordinary persocom: capable of thinking and learning on her own, she is a legendary type of robot known as a Chobit. Now, it is up to Hideki to teach Chii how to live an ordinary life and to uncover the truth behind the elusive chobits series.