Naō Matsudaira works as a live-in helper for the Murano family in their household, which also functions as a printing shop. The family consists of a widowed father who owns the shop, his four sons, and their elderly grandmother. Every thirteenth day of the month, the family maintains a solemn ritual: they visit the grave of the deceased wife and mother. During one of these cemetery visits, Naō encounters a trembling, frightened cat.

This encounter serves as a pivotal moment in the story, which continues from the events of a previously published one-shot. The serialization explores what happens next for Naō and the Murano family as time passes and brings new changes into their lives. The narrative focuses on the relationships within the household, the shared grief that binds them, and the small but significant moments that emerge from their routine of honoring the deceased on each thirteenth day.