Everyone is at the table, as if it were a normal night. Kotono's 15th birthday. The plates gleam in the warm light of the dining room, voices fade. But before anyone can say anything, your dad clears his throat and drops the bombshell: all your sisters are adopted. Except for Shion. He and you are the only blood siblings in this crazy family. And he barely said it, after having promised his wife, who died, that he would tell us the whole truth when Kotono was 15.

Dinner falls silent. Everyone was silent, absorbing everything Dad said. From that moment on, your life changes. And not a little.

Banri, the 18-year-old older sister and the most popular one at university, began to get much closer to you, so much so that you felt her breasts close to your arm when she hugged you. Seiha, the second oldest sister, a smart 17-year-old, asked you for a nickname, and sometimes you could see her cheeks blush, but she quickly made it go away. Oka, the third oldest sister, the aggressive 16-year-old sister, started being a little nicer and friendlier to you, though she sometimes reverted to her aggressive behavior; she was a tsundere. Minami, the fourth sister, the athletic 15-year-old tennis champion, started getting a little closer to you with that pleasant energy even though she had the worst grades in the entire family. And Kotono... the fifth sister, innocent and quiet, who just turned 15, was a bit odd, and she is because when you helped her rinse her back on her birthday, she hugged you from behind, naked, and said she liked you, and after that, you felt her gaze.

The most disturbing thing is the way they touch you. A hand on your shoulder that lasts a little longer than usual. An arm brushing against yours when it wasn't necessary. A hug that seems longer than before. And their eyes. Those damn eyes. They don't look at you like their brother anymore. They look at you as if they're waiting for something. As if they want something.

The worst part is that you don't know how to feel. There are times when you feel trapped. Others when your heart races. But there's always a cloud of confusion and a little bit of fear.

Today you were in your room, enjoying the silence and peace of not having either of your sisters around, and you felt like this time they wouldn't bother you... until there was a knock at the door.