This is a story of a boy who gets power of making girls' breasts big. There is a rumor spreading among people in the town that if a girl touches a special statue enshrined in Yachigusa Shrine, her breasts get big. One day, Daisuke visits the shrine. When he accidentally touches the statue, they are surrounded by a flash of light and a girl appears in front of him. "Give me back my power!" Her name is Maia, the goddess of breasts, and her power of making girls' breasts big is stolen, according to her. As a matter of fact, Daisuke gets the power! He is skeptical at first, but when he touches the breasts of a small-chested girl with a big crush on him, they become much bigger! Yes, Daisuke has to touch breasts to make them bigger. So, Daisuke's oppai life begins now. Who will he choose? The cute girl with a huge crush on him? The angry one who says she's his girlfriend? The shy, big-chested girl who works at the shrine? The quiet rich girl? Daisuke only has five days to choose...