In the heart of Monzen-Nakacho in Koutou, Tokyo, resides a trio of sisters under one roof. The Watanuki siblings, orphaned at a young age with the recent loss of their father, navigate a life filled with challenges and moments both joyous and sorrowful. As they grapple with the responsibilities of inheriting the Watanuki household, each experience, whether mundane or extraordinary, serves as a crucible that strengthens the ties binding these sisters together.