The sky was once a canvas of peace, a sanctuary for the weary. But now it lay as an eternal reminder of humanity's impending downfall. Six years ago, the demons finally came out of hiding. They used the humans as sacrifices for Satan's growing power. Gabriel Cain, a widower who had his everything taken from him, shall make it his duty to venture into hell with the Black Sun Resistance for the purpose of saving everyone and avenging those he lost.