Mech-pilot Aria has never wanted to be the Chosen One despite the fact she can hear the resonance of the black mech. When Aria is forced to accept the newly returned Chosen One, Ondes Martenot, into her squad after a disastrous first impression, she has no choice but to leave the coven and the only home she’s had since her biological family’s deaths. But rifts in time and space open because of the presence of Ondes’ black mech, letting a giant metal-and-flesh monster into the world, and Aria loses her second family.

Grieving and angry, she swears to make the Chosen One give up their power. When Ondes begs Aria to return and be a part of the squad again, she sees her chance. However, while by their side, Aria discovers that there’s more to being Chosen than singing a rift closed. Now she must give up her quest for justice, and if she can’t, the role of Chosen One might just become hers.