Yurika had been repeatedly seduced by her stepson Masaki. Masaki exploited the debt of gratitude Yurika owed to him—since her late husband, who was also Masaki's father, had financially supported her—and used it to pursue her body. By chance, her biological son Takayuki witnessed the affair. The relationship between mother and son gradually deteriorated, and the emotions Takayuki had long concealed within his heart unexpectedly transformed into jealousy.