The magical kingdom of Lucis is home to the sacred Crystal, but the hostile Niflheim Empire will stop at nothing to seize the relic. King Regis of Lucis leads an elite squad of soldiers called the Kingsglave. Armed with the king's magic, Nix Ulric and his loyal Kingsglave comrades defend the capital city of Insomnia to stop the inexorable advance of the imperial army.
Facing the superior forces of Niflheim, King Regis has no choice but to accept the ultimatum, ceding all his lands outside the capital and marrying his son Noctis to Lady Lunafreya, former princess of the now-captured land of Tenebrae. As the war rages on, the machinations of Niflheim turn Insomnia into a grand battlefield, drawing Noctis into a struggle for the survival of the entire kingdom.