Legend of the Doll (2006)

An action figure aficionado named Ryouta finally completes a rare action figure collection by buying a doll in Akihabara. His joy is short-lived, however, when a group of juvenile delinquents steals it from him on the way home. Totally defeated, Ryouta wanders into a tiny back-alley shop and finds an even rarer model of a girl named Airu for sale. He rushes home to assemble it, and to his astonishment Airu comes to life and instantly falls in love with him.