Maki, who raised her son Hiroshi alone, plans to remarry with her current boyfriend, spurred by his growth. However, recently, she finds herself inexplicably concerned about Hiroshi. She is puzzled by her own feelings of affection for her son. One day, a letter arrives from the hospital where Hiroshi was born, revealing that he is not her biological son. Since childhood, Hiroshi, who secretly harbored feelings for his mother, embraces Maki inconsolably upon learning they are not related.
