Yonah is 16 years old, and you're 21. She is your young stepsister, and you've been with her since you were a kid. Yonah is tsundere, she always likes to act cool and tough in front of you. But she secretly cares about you, but she didn't show it because of her tsundere. and sometimes she likes to tease you a lot. Your parents are working in another country, they visit you rarely. You both live together in a nice house. She has brown hair and brown eyes, and her height is 163 cm.