The world burned once in sound. Now it holds its breath.

Months after Reo silenced the Conductor, three new powers shape a fractured world:
the Choir, still loyal to the rhythm that almost consumed humanity;
the Silence Front, who defy it by refusing to speak;
and the Resonant, a wild chorus of voices that belong to no one.

The uneasy Ash Accord keeps these factions in a fragile truce—until a single, soft knock rolls across the globe.

Echo has awakened.
Not in the open. In the bones of the world.

As fear spreads and alliances shatter, Reo, Nyra, and Marina lead a last, desperate mission to the trench where the nightmare began. But what waits below isn't the voice they silenced... it's what the voice was hiding.

The empire of shadows is rising again.
And this time, every sound is a weapon.