Computers are supposed to make people's lives easier, but as Hideki is quickly finding out, taking care of your computer can be a full-time job! Regardless, Hideki is thrilled to have a persocom of his own - the enigmatic Chi - even if she isn't as user-friendly as other computers. His friends tell him that Chi is a supercomputer, possibly a legendary Chobit - an AI. That would explain why she acts so human. Maybe she's a little too human. The more time Hideki spends with Chi, the more it feels like an actual relationship. But as Chi's feelings for Hideki intesify, she begins to unlock the secrets of her past... secrets that are better left forgotten.