Legaia 2: Duel Saga is centered around a group of people known as "Mystics"; these people are outcasts, usually shunned by the rest of the common folk who mistake them for monsters. It is not without reason, though, since they can summon nature spirits called "Origin".
One of these Mystics is Lang, a youth adopted by the militia leader of the small village of Nohl and recruited into its defense force to protect the Sacred Azure Stone, a mysterious crystal which supplies the town with endless water.
The game begins on Lang's first day at work, which sets a series of events into motion that ultimately put the fate of the world in danger. Started with the ambition of a Mystic to creating a new world by destroying the current one, Lang teams up with his fellow adventurers to save the world.