Ruby is a rare black mage in a kingdom that worships holy mages and treats her magic as savage. Her only solace was her half-sister, the Holy Maiden Floria, who seemingly accepted her. However, Ruby discovers it was all a lie: Floria manipulated her into using black magic for horrific human experiments. Executed for these crimes, Ruby suddenly wakes up years in the past. Determined not to be fooled again, she vows to use her black magic to protect the kingdom from the Holy Maiden and survive. This time, the once-isolated Ruby finds unexpected love and allies, turning her shunned abilities into a magic of justice in a thrilling tale of betrayal and redemption.