While visiting his friend's house, Kobayashi falls in love with his friend's kind mother, Mitsuha. The woman he falls in love with is married, and moreover, his friend's mother. He knows it's a love that shouldn't come true, but he can't give up. Kobayashi is so curious about Mitsuha that he sneaks out of his room to check on her, but there he learns a shocking truth. His secret feelings for Mitsuha, which he had intended to keep as mere admiration, begin to spiral out of control...