"Ebullient Future" is the instrumental opening theme for the anime series "Ef: A Tale of Melodies." Composed by Tenmon, a pianist and composer known for his work on anime series like "Makoto Shinkai's Voices of a Distant Star" and "5 Centimeters per Second," the piece is characterized by its melancholic yet hopeful piano melody, which perfectly sets the emotional and romantic tone of the visual novel-based anime.