"Was I just a replacement from the beginning?"

On the night of his father's funeral, a college student named Yamato meets a man who leaves a big impression on him. He doesn't give his name, but leaves behind some words that stick in Yamato's mind. "Are you his son? You look much like him." Several days later, much to his surprise, Yamato meets the man again, and beneath the moonlight, their love secretly begins…