Luna, a saint who once saved countless people with her overwhelming power, was unjustly executed despite her deeds. Three hundred years later, she is reincarnated—retaining her power. “I swear… no matter who’s in trouble, I’ll never help anyone again. I’ll become a villainess instead!” Determined, she aims for the villainess position at the Saint Academy, while hiding her true identity under full armor and working as an adventurer. But wherever she goes, her overwhelming saintly powers cause nothing but massive trouble…!?