Orange is a romance/high school drama with a speculative twist. Sixteen-year-old Naho Takamiya discovers a letter from herself from ten years into that future that tells her to watch for a new transfer student, Kakeru Naruse, who will become one of her friends. Though happiness has not eluded future Naho, she has many regrets over things that she wishes her younger self had done differently.
As predicted, Kakeru joins her class that same day, and he’s quickly absorbed into Naho’s circle of friends (both male and female). Though she knows from her letter that Kakeru will not live to see the end of the school year, teenage Naho can’t help falling in love with him.