Naho Takamiya, a high school sophomore, receives a mysterious letter during springtime, penned by her future self a decade ahead. The letter reveals her affection for Kakeru Naruse, a new student burdened by the trauma of his mother’s suicide, who tragically passes away a year later. Now 26, Naho frequently reflects on Kakeru. Armed with insights from her future self, the younger Naho is determined to alter the course of events and reshape her destiny.