The slender, big-breasted single mother who lives next door always acts cheerfully, but somehow she seems lonely.

Moved to Tokyo to attend university. The life I was living alone, which was supposed to be full of hope, turned into a lifeless life where I didn't talk to anyone. One day, Luisa, a single mother with her young daughter, moved into the next room. For some reason, I couldn't leave her alone as she was desperately trying to be a mother with her small back. It was supposed to be a small help. However, her smiling words, ``Thank you,'' touch my heart. Before I knew it, Luisa's presence had become the color of my world. The two of them are lonely, but little by little, their hearts and bodies come closer together. However, that calm time did not last long. What appears is her past - her ex-husband, Tatsuro. I was paralyzed by the yelling and violence. I'm helpless. That's what I thought. But when I saw those tears, my heart screamed. "I'll protect you." Even if I'm cowardly or pathetic, I'll stand up for the sake of your smile.