Reina, who is always carefree and innocent, gets revenge on her sister for scolding her by "cutely and cunningly" cuckolding her sister's boyfriend! Reina, who is scolded by her sister every day, finally explodes with frustration and comes up with a plan to seduce her sister's boyfriend. When he comes to stay over for the weekend, she takes advantage of her sister's absence to seduce him with "cute gestures" and "cute words" that make the most of her natural Ke'ai and bouncy big breasts... She looks like a little devil! But if she can do something so naughty, maybe she doesn't mind being tricked!?