Summary: Nex is a freelancer demon huntress who faces enormous economical problems due to her finite and destitute clientele. One day, a mysterious person approaches her, requesting her services and promising to award her handsomely. However, Nex will discover this mission and the rest asigned to her afterwards are not her usual demon extermination, but the arrival of the strongest demon lord of all times. The salvation of the entire nation lies on her hands, while she must also face the insuperable burden of her past, which is tightly linked to the missions. But is she really alone against this menacing threat?