Okamura Aya experienced her mother's frequent absences during childhood due to overseas medical work. To help her cope, her father brought home a kitten named Mii, who became her constant companion. This established her reliance on the cat and her family bonds.

Seeking career independence, Aya moved away from home roughly two years before the main events, leaving her father with the aging Mii. She navigates typical workplace challenges, facing demanding days and professional stress, including reprimands from her boss. After one difficult day, she retreats alone to her apartment, highlighting her self-reliance and isolation.

Her relationship with her father grew strained following her move. She consistently avoids spending time with him, declining dinner invitations with excuses about work. This distance reflects her prioritization of independence and adult responsibilities over family connections, implying unresolved tension.

A pivotal change occurs when she learns of Mii's declining health and subsequent death. This news prompts her immediate return home, catalyzing a reconciliation with her father. Sharing a meal and reminiscing allows them to reconnect emotionally. Later, she visits again to meet a new kitten her father adopted. During this visit, her mother returns from overseas, reuniting the family and restoring their happiness.

Throughout this journey, Aya evolves from an independent but isolated professional to someone who re-embraces familial bonds, recognizing their enduring importance. The cat Mii, and later the new kitten, symbolize continuity and the healing of family ties across different life stages.