Six prodigies attend Kanezono Academy of Music, each with a mysterious past and a “color” tied to their soul’s melody. The story follows Ren Hayami, a withdrawn violinist who hasn’t played since his sister’s suicide. On his first day, he hears her melody echoing through the old concert hall—played perfectly by a girl he’s never met.
Soon, Ren and the other students are drawn into the “Symphony of Souls”, a ritual that binds their emotions to music. Every performance drains something from them—memories, feelings, or fragments of life itself. To graduate, they must each compose their Final Piece, but the truth is grim: only one can complete it, and the rest will vanish into their own unfinished songs.

Nagi presented Ren with a small key shaped like a treble clef. "This opens the place where the first melody was born," he explained. "It's hidden under the stage. Few have ever seen it. It contains music older than Kanezono itself."


"Because," Nagi said quietly, "you're tied to it. The academy senses it. You'll either master the melody… or be destroyed by it."


That night, Ren lay awake, the key clutched in his hands. Faint crimson threads pulsed along his violin bow, and the distant echo of Scarlet Strings called to him again.


The next step is beneath the stage. And once we go down… there's no turning back.


Chapter 20 - The Tuning Key