I used to keep in close touch with my younger brother Takashi, who moved to Tokyo for college, always sharing everything like best friends. When I visited Tokyo after a long time, I ended up staying overnight at Takashi's place. But when I finally saw him again, he had completely matured, and introduced me to his girlfriend, whom he called "Sara." Upon learning she was my sister, I found myself irresistibly drawn to her charm, overwhelmed by intense emotions stirring deep within me.