Two years after the convergence of Sylvarant and Tethe'alla into a single world, the unified realm descends into chaos as useless maps, destabilized weather patterns, and resurfacing animosities between the merged peoples ignite widespread conflict. When violence erupts between the Church of Martel and the rebel faction known as the Vanguard, the city of Palmacosta becomes a battleground—its destruction in the event known as the Blood Purge is attributed to the legendary hero Lloyd Irving, though the truth remains murky. Among those caught in the devastation is Emil Castagnier, a hesitant youth orphaned in the massacre who seeks to uncover what truly transpired. His search intersects with Marta Lualdi, a mysterious girl burdened with the Core of Ratatosk, a dormant celestial being whose awakening has destabilized the world itself. Together, Emil and Marta embark on a quest to restore equilibrium to their fractured land, with Emil swearing allegiance as a Knight of Ratatosk.