The series follows Tetsuro Koyanagi, a rigid and work-obsessed salaryman whose life is turned upside down when his wife suddenly leaves him, abandoning their seven-year-old daughter, Rin. Having prioritized his career over his family for years, Tetsuro finds himself completely unprepared to handle the responsibilities of single parenthood, struggling to connect with his daughter who has grown distant and quiet in his absence. As the story progresses, Tetsuro is forced to re-evaluate his priorities and his definition of success. Through the daily challenges of raising Rin, he begins to understand the emotional needs of his child and the importance of human connection. The drama serves as a poignant exploration of fatherhood, personal growth, and the healing power of family bonds, highlighting the transformative journey of a man learning to be a true parent.