My little sister is an 18-year-old beauty. Though she occasionally acts a bit cheeky, she's actually caring and dependable, always looking out for me. Lately, she's been giving off a strangely seductive vibe, stirring something deep within me. The way she constantly calls out "Onii-chan, Onii-chan" shakes something inside my heart, gradually breaking it down. Everyday life with her feels like a dream.