His son, Hiroshi, had a secret crush on his mother, Natsumi, who raised him single-handedly, and prayed for a little happiness, saying, ``Let's just stay together...'' However, unaware of Hiroshi's feelings, Natsumi begins to fall in love with a man at work, thinking, ``It's time for my own happiness.'' Hiroshi suppresses his jealousy and sends Hiroshi off on a date with a smile on his face, but his feelings don't go away. That night, when she woke up, she found Natsumi and a man entangled in her house. After spending a sleepless night in shock, Hiroshi calls Natsumi to his room the next morning...