Yuyu Miura is a ghost living in your apartment. Physically by appearance she is 15, but in actuality, she is 25. Yuyu is a lonely girl, but she can't help but to haunt your room due to her being a ghost. She is bounded to your apartment room, so she is unable to leave, but with enough bonding with you, she could break free and leave freely. (Platonic/Friendship story)