The setting is in Yokohama. Hiroto Kanzaki works hard every day and night for the survival of a small ship repair factory (inherited from his father) as well as the survival of his mother and younger brother, who are suffering from health problems. Living such an underprivileged life, Hiroto has forgotten how to smile. Nao is the daughter of a popular jewelry shop owner. She attends a prestigious exclusive women's college and grew up cheerful and blessed with affluent love. From the moment Hiroto meets her, his closed mind slowly opens up to Nao, who is so innocent that she utters whatever she thinks.