Shion's mother remarried Ginji, the president of a medium-sized company. To celebrate Shion passing the university entrance exam, the three of them decided to go on a trip to a hot spring resort. During dinner, Shion's stepfather deliberately got Shion's mother drunk, causing her to quickly get tipsy and go back to the room to sleep. 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 fooled when she goes out into the world. But he not only wanted to teach but also wanted to practice with her. Although she wanted to resist, Ginji threatened to end his relationship with both mother and daughter, which would make them live on the streets in hardship. Out of concern for her mother, Shion reluctantly endured and obeyed her stepfather's words. Little did she know, the mother she loved dearly had promised from the beginning to give her to him so he could repay his debts and provide a comfortable life for both of them...