Fujishirou Kousuke is currently an unfriendly and unsociable high school student. However, when he was younger, he made a promise with his childhood friend, Sayaka, that they would get married when they grew up. But one day, Kousuke is kidnapped and taken to a place that strangely resembles a prison. Little does he know though, is that this "prison" is guarded by very voluptuous women... Can Kousuke remain a virgin to fulfill his promise to Sayaka?