Shion's mother remarried Ginji, the president of a mid-sized company. To celebrate Shion's passing the university entrance exam, the three of them decided to go on a trip to a hot spring resort. During dinner, the stepfather intentionally poured alcohol for Shion's mother, causing her to quickly get drunk and return to the bedroom. Shion intended to go with her mother but was held back by Ginji. He wanted to teach her about love experiences so she wouldn't be deceived in the real world. However, not only did he want to teach, but he also wanted to practice with her. Despite wanting to resist, Ginji threatened to end the relationship with both her mother and her, forcing them to live a miserable life on the streets. Out of love for her mother, Shion had to endure and obey her stepfather's words. Little did she know, the mother she dearly loved had promised from the beginning to give her to him, so that he could repay debts and provide a prosperous life for both of them...