Akira's ordinary routine shattered when the world fractures. His older sister Haruka guards a dangerous secret, an inherited ability called "Engine" that marks her as something beyond human. While she struggles to keep her power hidden from a world that would weaponize it, Akira wrestles with his own inadequacy. He inherited nothing from their father, left without the gift that runs through his family's blood. When catastrophic phenomena begin erupting globally, the line between normal and extraordinary collapses. Haruka's secret becomes impossible to contain, and Akira discovers that powerlessness carries its own kind of weight. As mecha rise from the chaos and the Engine's true purpose reveals itself, both siblings must confront what they're willing to sacrifice. Vertex Force strips away the comfortable life of a quiet cafe and forces a family to answer impossible questions about destiny, power, and what it means to belong to a war they never chose. Haruka and Akira must navigate a transformed world where their hidden past suddenly determines everyone's future.