The world lies submerged beneath a catastrophic deluge unleashed by the Pureland Water Entity, a primordial force that has dragged monsters into civilization and left coastal settlements in ruins. When four warriors resolve to challenge this ancient threat, they're joined by unexpected allies—young fighters materialized from the future—who reveal a troubling truth: the Entity's rampage spans across time itself, ravaging past and present eras alike. Realizing that victory demands coordinated action across temporal boundaries, the unlikely party embarks on a perilous quest to recover the scattered components of the legendary ship Talon, gathering its pieces from multiple eras to forge the weapon necessary for confronting their catastrophic foe.