Boku no Imouto wa "Osaka Okan"

Kyosuke reunites with his younger sister Namika after ten years apart, only to discover how thoroughly Osaka has shaped her. Her blunt speech and distinctive habits bear little resemblance to the sister he remembers.

Ordinary life at home becomes a running lesson in regional differences. Between his surprise and her quick responses, the siblings have to learn who they are now rather than rely on the childhood bond they left behind.