Rune was born with a sun-like crest on her wrist (known as the Crest of the Sun), and was told by her grandfather that she was the reincarnated Space Queen. Rune refuses to believe almost anything her grandfather says and tries to live a normal life, despite the fact that she works part-time as a cybernetic superhuman to ward off alien beings that have invaded the earth. Rune's childhood friends, Masaya and Masato Ibayashi, are also cybernetic warriors who bear the Crest of the Sun, but she doesn't know this until later in volume one. It is also revealed that her other close friend, Aina Hazumi, is also a Crest-bearer.
