Hideki Motosuwa is a 19 year old trying to pass the entrance exams to enter college. He has a job working in a restaurant, but he's perpetually broke, and his family isn't very well-off, either. What he really wants is a Persocom, a computer in the form of a man or a woman. Unfortunately, given his financial situation, he won't be able to afford one any time soon, and it seems that he's one of the very few who can't afford one.
Persocoms are very popular. In fact, people who have them seem to spend more time with their Persocoms than they do with other flesh and blood humans. The only way to tell a Persocom apart from a human is by their ears, which look like truncated cones, and which are a series of ports that humans can use to access the data inside the persocom. While male models do exist, most persocoms are actually nubile-looking females. There also exist smaller persocoms, about baby-doll size, that are laptops and even smaller ones that are PDAs, although few of those are modeled on humans.
One night, Hideki is on his way home, bewailing his lack of a persocom, and he finds one, all wrapped up, left on top of some sacks of garbage. At first thinking that he's found a dead body, he freaks out, only to realize that it is a persocom by the ears.
Gladly making off with his prize, he takes her home, and then tries to figure out where her activation button is. Eventually, he finds it... right between her legs, which squicks him out a good deal. He then plugs her in and finds that she has no software, making her useless... or does it? She can only say one thing, "Chi!," which he soon gives her as her name. He calls on a friend from cram school for help, but Chi crashes his friend's laptop persocom, Plum. His friend is upset about this, but gives Hideki the name of a boy who seems to know more about constructing his own persocoms than anyone, and sends Hideki to see him.
Once again, Chi wreaks havoc among the off-the-shelf Persocoms, and the boy tells Hideki that Chi may be a "Chobits", a Persocom with an AI capable of thinking on its own and learning in the same way. So far, Chobits are only the stuff of urban legends, and he promises to look into it and find out more for Hideki.
Hideki, with Chi living with him, is afraid that people will think he's a pervert because all the clothing Chi owns (given to him by his landlady due to his usual shortage of cash) are all clothes with a high fetish value, like a schoolgirl outfit or maid outfit. And given that Chi has no sense of body modesty and she was nearly falling out of the first set of clothing he could find (his own, which were much too big for her), he constantly finds himself embarrassed around Chi.
This series is amazing, taking something that some people worry about (people spending more time with their computers than other humans) and adding to it by having the computers be nubile young women. Although not in this volume, but in later ones, it is implied that male users even use their persocoms to have sex with (if you could call it sex and not masturbation with an object, considering that persocoms don't really qualify as another person). Chi, of course, is immune from that considering where her on/off switch is located. More than that, Hideki treats Chi as he would a human girl (or as a child sometime, because she is learning as she continues to operate), and not simply as a computer.
The author adds to the creepyness factor by having a storybook which describes humanities obsession with persocoms without naming what it is talking about. In which the narrator, who looks like the bunny PDA possessed by one of the characters in the manga, talks about a city with no people, for all the people inside with "them".
So, what is a Chobits? We have yet to find out, but the beginning is intriguing, and speaks to humanity's obsession with our tools, in this case, computers.