There are three sisters: 29-year-old Sachi Kouda (Haruka Ayase), 22-year-old Yoshino Kouda (Masami Nagasawa) and 19-year-old Chika Kouda (Kaho). They live at a house in Kamakura, Japanese. Their house was left by their grandmother.
One day, they receive news of their father’s death. When the sisters were young, their parents divorced and their father left them. They haven’t seen their father in 15 years. Upon hearing the news on their father’s death, the sisters attend their father’s funeral.
At the funeral, they meet their stepsister Suzu Asano (Suzu Hirose). She is 14-years-old and there are no one to take care of her. Oldest sister Sachi invites Suzu to live with them.
Based on the manga series “Umimachi Diary” by Akimi Yoshida (first published August, 2006 in Japanese monthly josei manga magazine Flowers). “Umimachi Diary” won the 6th Manga Taisho in 2012 and the Excellence Prize for manga at the 2007 Japan Media Arts Festival Awards.