With another Wave happening in a week, Naofumi Iwatani and his party have no time to waste. However, when bat familiars raid Lurolona Village and the Wave countdown comes to a halt, the Four Cardinal Heroes reconvene with the queen, Mirelia Q Melromarc, for a quick briefing. The queen presumes that the odd occurrences are linked to the Spirit Tortoise—a threatening creature that has awakened from its slumber, back to cause havoc once again. A plan to put the Spirit Tortoise to rest is devised—but out of the four men, only the cursed Shield Hero agrees to help.