Masaki was informed by his employer that he was to be transferred to the city of Rokujou, far away from Tokyo. As he was preparing for the move, he received a request from his parents to live with his aunt and her family while checking up on how her marriage is doing. He was reluctant to interfere with other people’s business, but finally relented under his parent’s deep worry for his aunt’s marriage.

He was welcomed to the city by his aunt Kyouko and her daughters Mizuho and Kotomi. He had met them once a long time ago, but he was astounded by how beautiful they’ve become, how voluptuous their bodies had grown. Will he be able to keep his wits living under the same roof with them? Moreover, his new supervisor at work is an American blonde beauty with a figure that rivals theirs. Did he wander into a kingdom of big tits and asses?