Based on the erotic game by Lune Team Bitters. This is a story about Sayaka and Masaharu, college juniors, who are about to get married together. Everyone knows Sayaka to be a conservative woman and is saving sex for after marriage. However, Kaneko-senpai, considered to be a reliable senior by Masaharu, has other plans to change Kudou’s mindset. He finally gets his chance after Masaharu cancels due to work and he takes it. Will Kaneko succeed in his evil deeds to turn Kudou Sayaka from a conservative woman into a horny slut?