Sevens are humans with unique abilities that will exist in the near future. The country appears to be kept in peace by the Sumeragi Group, but they are the ones who kidnapped people with extraordinary abilities and subjected them to terrible experiments. Gunvolt, the primary character with the Sevens power, used to be a member of Feather, a resistance group that fought the Sumeragi Group. Sian, the heroine, is introduced at the start of the novel.