平凡な日々を送る、恋愛経験ゼロの大学生・四葉 楓(よつば ふう)の日常は、ある日一変する。
学内の誰もが憧れる先輩・鴻上沙羅(こうがみ さら)が、自分は並行世界から来た存在で、”自分たちは恋人同士だ”と一方的に告げてきたのだ。
言葉も交わしたことのない沙羅からの突然の告白に戸惑いながらも、次第に惹かれていく楓。
しかし、やがて自分は彼が愛した並行世界の楓ではないという葛藤に苦しみ始める。
一方、沙羅にも大きな秘密があって…。
運命の糸をたぐり寄せて出会った二人が選びとる愛の行方は ──
The ordinary daily life of Yotsuba Fu, a college student with zero romantic experience, is suddenly turned upside down one day. The senior admired by everyone on campus, Kogami Sara, abruptly tells him that he is someone who came from a parallel world, and that “we are lovers”, declaring it unilaterally.
Confused by this sudden confession from Sara, with whom he has never even exchanged words before, Fu nevertheless finds himself gradually drawn to him. However, he soon begins to suffer from the inner conflict that he himself is not the Fu whom Sara loved in that parallel world. At the same time, Sara is also carrying a major secret of his own…
Guided together by the threads of fate, what path of love will the two ultimately choose?