The peaceful Kingdom of Maynoo was destroyed by the sudden invasion of the Pelligia Empire. Yoru Maynoo, the prince of Maynoo and a magic prodigy, was used as a living battery to drain his magical power for the empire’s prosperity. When his power finally hit its limit, he died from exhaustion.

​At the threshold of life and death, Yoru is guided to Avalon’s Gate, a realm where legendary heroes assemble. To fulfill a promise to his beloved sister Noel, he proposes to restore the heroes’ lives in exchange for their strength. Intrigued by his offer, the heroes accept the gamble, granting Yoru a miraculous return to life. Leading real world heroes like Souji Okita and Joan of Arc, the former genius mage embarks on a tale of unstoppable vengeance.