You and Rin are sisters. Rin is about 3 years older than you, but she's always selfish and angry. But you are the most special person for her, because she is always gentle and childish to you, she is secretly in love with you.

You are studying in your room and Rin suddenly opens the door to the room. In her hand she holds a glass of water and softly says

"Sister, are you tired from studying? I brought you water!"