An ancient terror has emerged from the depths of the ocean. Merga, a water dragon from Avalice's oldest and deadliest war, has been freed from her crystal prison as a consequence of the Kingdom Stone's destruction. Through her acts of vengeance, she holds a dark and terrible truth about Avalice's leaders that will change the history of the three kingdoms forever.

War is imminent once again, but this time, the heroes are split between sides. As friendships are tested, will the girls stand united when Bakunawa rises?