Hortensia, a kingdom that has stood for over 700 years, is attacked without warning by Camellia, one of its principalities, leaving young Alfred Albert, heir of Albert's Dominion, to grow up quickly and lead his people in defense of the kingdom.

Monsters from Magonian folklore become widespread, prompting a curious boy to see the legendary monster of a nearby cave, and ends up missing. But when Alfred and the others go to investigate the cave, it calls up unpleasant memories for Marius.

Albert and Maurice are summoned to the capital to meet with the captain of the Ecclesiastical Order, who tasks them with clearing out the undead monsters of Petale Village, which was wiped out some time ago by the effects of a dreadful plague.

The party heads to the capital to allow Alfred and Maurice to report directly to Captain Georg. However, along the way, they pick up a pair of young Dairean twins, ostensibly survivors of a monster attack, who take a special liking to Alfred.

Seeking moderate allies within the kingdom, Captain Georg asks Alfred and the others to seek out Adelheid, heiress of Olivier's Dominion. However, tensions escalate when Didier and the Ecclesiastical Knights arrive to arrest Adelheid.

Alfred and his entourage are sent to Juin Island to investigate a claim that the missing Princess Marielle is living in exile there. Matters are complicated when Thalia and Elva also arrive to determine if the so-called princess is genuine.