Daikichi Kawachi, a 30-year-old bachelor with a stable but unremarkable office job, attends his grandfather’s funeral and discovers that the elderly man had secretly fathered a child late in life. The child, Rin Kaga, is a quiet and reserved six-year-old girl who has been largely ignored by the rest of the family due to the scandal surrounding her birth. Feeling a sense of responsibility and compassion, Daikichi decides to take Rin into his care, despite having no prior experience with parenting or childcare.

As Daikichi adjusts to his new role as a guardian, the series explores the challenges and rewards of raising a child. Rin’s presence forces Daikichi to reevaluate his priorities, leading him to make significant changes in his lifestyle, including moving to a smaller apartment and taking on more flexible work hours. The narrative delves into the daily routines of their lives, highlighting the small but meaningful moments that shape their relationship. Rin’s reserved nature gradually softens as she begins to trust Daikichi, and the two form a deep, familial bond.

The story also examines the reactions of those around them, including Daikichi’s coworkers, friends, and family members, who offer varying degrees of support and skepticism. A key figure in their lives is Kouki Nitani, a single father and Daikichi’s coworker, who becomes a source of advice and camaraderie as Daikichi navigates the complexities of parenthood. Rin’s biological mother, Masako, remains a distant and enigmatic figure, adding an undercurrent of tension and mystery to the narrative.

Over time, Daikichi and Rin’s relationship evolves into one of mutual dependence and affection, with both characters growing and maturing through their shared experiences. The series portrays the realities of single parenthood with a grounded and heartfelt approach, emphasizing themes of responsibility, sacrifice, and the transformative power of love. The story avoids melodrama, instead focusing on the quiet, everyday moments that define their lives together, creating a poignant and relatable portrayal of family dynamics.