Through his parents' remarriage, the protagonist has gained a new stepsister. Leaving the two of them behind, their parents set off on their honeymoon. The protagonist, who loves little-sister stories, sees this as his chance and wants to somehow build a good relationship with his stepsister. However, she is strong-willed and openly hostile toward him. But right now, the two of them are alone in the house… Whatever happens, it won't be a problem as long as he keeps it under control.

The protagonist resolves to start a sexual relationship with his stepsister by any means necessary. Even if that means as lovers, or as his cum dump…