Naofumi Iwaya, the Shield Hero who defeated the Four Sacred Beasts, the "Spirit Turtle", defeated Kyo, the culprit behind the resurrection of the Spirit Turtle in the other world, and returned to Melomag. He tried to prepare for the battle with the new Four Sacred Beasts, the "Phoenix", which was about to be resurrected, but the three heroes who failed in the Spirit Turtle riot disappeared, and Naofumi Iwaya's territory was also in an uncertain situation of strength. In order to retrieve the scattered residents of the former Lulorona Village and prepare for the upcoming battle, Naofumi Iwaya visited Cerutobul, where the residents were sold into slavery. As the first step to rescue them, Naofumi joined the underground arena with Raphtalia and Filo, the demi-humans seeking redemption, the heartbroken three heroes, and Myne lurking in the shadows. When everyone's plot intersects, can Naofumi Iwaya take the path he believes in?