Orange

One day, Naho Takamiya receives a letter from her future self, written ten years from now. The letter accurately predicts everything happening that day, including the arrival of a transfer student named Kakeru Naruse. Her future self confesses she has many regrets and hopes to guide Naho toward better choices—especially concerning Kakeru. Most startling of all, she reveals that ten years later, Kakeru will no longer be alive, and she begs Naho to look after him closely.