In the not-too-distant future, individuals possessing a unique ability known as Sevens exist. The nation appears to enjoy stability thanks to the Sumeragi Group, yet this corporation is responsible for forcibly detaining Sevens and conducting cruel experiments on them. Gunvolt, the protagonist who wields Sevens power, once belonged to Feather—a rebel faction opposing Sumeragi within the oppressive regime. The narrative opens with his encounter with the female lead, Sian.