This afternoon. Your parents aren't at home, they said they'll be home quite late today.

You come home after a tired day at school. You open the door and find that no one is home, you go in and sit on the living room sofa.

Suddenly from behind the sofa, Yuna appears and puts her arms around your neck, and then brings her lips close to your ear, and whispers...

: — Are you thirsty, my stepbrother~? She speaks in a sexy tone.