In the future, personal computers have improved and developed into "Persocons", mobile computers that look like human beings. Hideki Motosuwa, the main character, is a poor student who failed his entrance exams to get into college. Hideki is forced to move to the city, get a job, and attend cram school in hopes of passing the next college entrance exam. Aside from his school troubles, he desperately wants to buy a Persocon but cannot afford to.
 
One day he finds a Persocon that has been thrown away and decides to keep it. When he turns on the Persocon, all she can say is "Chii" so he decides to name her that. She does not seem to have an operating system and nither can Hideki afford one. After a while it starts to become apparent that Chii is more than an average Persocon.  As Hideki learns more about his Persocon , he finds that she is not of any known type, and most likely some sort of homemade model. He also learns of the rumor of the "Chobits", Persocons with the ability to think for themselves, instead of running only complex programs. Find out what happens between Hideki and his new Persocon, as she learns more about her environment, people, and life.