It all began ten years ago. D2s attacking Boston, a blood-soaked concert hall: The incident known as the Boston Tragedy. The conductor who lost his life in that tragedy was none other than Kenji Asahina, Takt's father. After losing his father, the boy decides to devote himself to playing the piano and he lets his rage play through his melodies. The one who took care of him was a girl named Cosette, who looked just like Destiny.

Anna and Destiny happen to see a town destroyed during their travels. D2s are awakening everywhere and attacking various towns and people, reverting the world back to four years ago, before Sagan's Declaration. As the threat from the D2s grew, Takt was obsessing over something. With a blank staff notation in front of him, Takt plays an imaginary keyboard as he desperately tries to create something.

Lenny remembers his own past. Lenny recalls someone very dear to him. Everything leading up to today was so that he could do everything he could to do what he had to do. Lenny heads to the meeting point along with Titan so they can tell Takt and Destiny everything. But someone rather unexpected was waiting for them.