Naral Island is located in a world of adventures and magic. Every generation, a Demon Lord emerges to wreak havoc on the earth, and every generation, a Hero is born to defeat him. The cycle has continued indefinitely, with no end in sight. Juulia "Yusha" Charldetto, the current Hero, is nearly through with her courageous quest alongside her party members: responsible priest Seiran "Seira" Élénoir, intriguing wizard Meiza "Mei" Endust, and hyper-energetic fighter Fai Fai. Yusha's crew attempts a dangerous spell to throw the Demon Lord into the drifts of time in the last fight. But the ritual fails, transporting Yusha and her comrades back in time to before the Demon Lord, before Yusha becomes the Hero, and before the group was even formed.