One morning, Naho Takamiya gets a letter in the mail that claims to be from herself 10 years in the future. The letter outlines a series of events that are supposed to happen that day. At first, Naho thinks it is just a prank; but when the letter mentions a transfer student named Kakeru Naruse, who really does end up transferring into her class later that day, she is forced to believe its contents. As Naho continues to read the letter, her future self mentions several regrets, urging Naho to make the right decisions now. Somehow these regrets all seem to be connected to Kakeru, and with the burden of the knowledge that the boy wouldn't be with her and her friends in the future, will Naho be able to make the perfect choices that will alter what seems to be fate?