At just 16 years old, Setsuna Mudo is often bullied by his older peers and secretly harbors romantic feelings for his sister, Sara, whom he only sees once a month. To avoid trouble, Setsuna keeps a low profile. But one day, his life changes when he is attacked by unearthly beings - angels and demons. Both factions claim to know Setsuna's true purpose: the angels believe he is the reincarnation of their leader, Alexiel, while the demons insist that Setsuna once commanded them in battle against God. Struggling to understand his identity amidst this surreal experience, Setsuna must also confront the looming war between Heaven and Hell. The question is whether he has the strength and bravery to face the coming storm.