Until the Defiant Stepsister Falls

The protagonist gains a new stepsister after their parents remarry.Leaving the two behind, the parents go on their honeymoon.

Seeing this as an opportunity, the protagonist—who loves “little sister” stories—wants to somehow build a good relationship with his new stepsister.However, she has a strong personality and is openly defiant toward him.

But now, the two of them are alone in the house… and as long as he can keep things under control, nothing will be a problem.The protagonist resolves to do whatever it takes to form an intimate relationship with her—whether that ends up being as lovers… or something far worse.