Naru becomes a celebrity all across Japan as an idol and this, of course, leads to Keitaro worrying about her studies. He begins to believe that Naru no longer cares about getting into Tokyo University and becomes incredibly depressed.

Keitaro discovers a doll that can move on its own. Everyone is amazed by it but Keitaro seems to be able to hear it talk also. He finds out from the doll that his great grandfather promised to fix its legs but never did and being the good guy he is, Keitaro decides to fulfill his ancestor's promise.. With the help of the girls, of course!