The story centers on , a high‑school sophomore who returns to his family’s countryside home for the summer. He discovers that his older sister Haruka —who left home years earlier to pursue a career in a city’s underground music scene—has returned unexpectedly. Haruka’s demeanor is a striking mix of “tough‑girl” swagger (leather jackets, dyed hair, a penchant for motorcycle culture) and an almost maternal protectiveness toward Takumi.