Akira lives a peaceful life with his older sister Haruka and his mother, who runs a cafe. The family, however, harbors a secret — Haruka has inherited a power from her father called "Engine," and she hides that power from others. Akira, on the other hand, has not inherited his father's power, and he has an inferiority complex about it. Amidst this, strange events begin to occur around the world.