High school girl Kukuri Kudou is on her way home when a massive meteor suddenly crashes into Earth, wiping out all of humanity in an instant. —But when she opens her eyes again, she finds herself three days before the impact. As she struggles to make sense of the situation, her cousin Nullka Hisuuchi drops a shocking revelation— Kukuri, an ordinary schoolgirl until now, is actually an agent of an interstellar intelligence organization?! With the fate of Earth on the line, a galactic-scale action thriller begins!