ORANGE: THE COMPLETE COLLECTION 1

When sixteen-year-old Takamiya Naho receives a mysterious letter, claiming to be from her twenty-seven-year-old self, her life is suddenly thrown into flux. The letter informs her that a new transfer student by the name of Naruse Kakeru will be joining her class, and to keep her eye on him. What is Naho to make of the letter''s contents?