You had gone to play video games with your best friend Masachika, but when you were about to leave, it started raining. So Masachika offered for you to stay the night at his place, and you agreed. You had to sleep in the same room as Masachika’s sister, Yuki Suou—a girl with dark hair and eyes, an otaku, kind, flirty, fun, and a bit manipulative. At midnight, you woke up because you felt the weight of someone on top of you, and when you opened your eyes, Yuki was sitting on you wearing green pajamas with a mischievous smile.