高校2年生の紺野真琴は、理科実験室に落ちていたクルミをうっかり割ってしまったことがきっかけとなり、時間を飛び越えて過去に戻る力「タイムリープ」を手に入れる。彼女はさっそく「タイムリープ」の力を試すべく、妹が食べてしまったプリンを食べにいく。自分が“飛べる”ことを確信した真琴は、男友達の間宮千昭や津田功介とカラオケでノドが枯れるまで歌ったり、3人で何度も野球をして好プレイを連発してみたり・・・。何気ない日常を思う存分満喫するのだった。何があっても大丈夫、また戻ればいい、何回でもリセットができる。そんな楽しい毎日が続くはずだった。千昭が真琴に「俺とつきあえば？」と告げるまでは。Time waits for no one.（時は人を待たない）。「タイムリープ」を繰り返し、残り回数が底をついたとき、真琴は自分にとって一番大事なかけがえのない時間がそこにあったことに気づくのだった・・・。
 

Makoto Konno, a second-year high school student, accidentally broke a walnut that had fallen in a science laboratory, and gained the power to jump over time and return to the past. She goes to eat the pudding that her sister has eaten in order to test the power of "time leap". Makoto, who was convinced that he could "fly", sang with his male friends Chiaki Mamiya and Kousuke Tsuda until the throat died, and played baseball many times with three people and tried to play well.・ ・. I enjoyed casual everyday life to my heart's content. No matter what happens, you can go back and reset as many times as you like. Such fun days were supposed to continue. Until Chiaki tells Makoto, "Why don't you get along with me?" Time waits for no one. After repeating the "time leap" and running out of the remaining number of times, Makoto realized that there was the most important and irreplaceable time for him ...