Synopsis: Shishunki Miman Okotowari

After Higuchi Asuka's mother passes away, she receives some unexpected news about her father. Armed with only his family name, Sudou, Asuka embarks on a quest to find him. Along the way, she intervenes in a potentially dangerous situation involving a man and a young girl. Asuka's actions lead her to the Sudou family, consisting of Manato and Kazusa, but their father is missing, and their mother has long since passed away. Desperate for answers, Asuka decides to take on the role of Neesan (big sister) and live with the Sudous until their father returns. But as she becomes more entwined with the family, complicated feelings begin to develop.