Final Fantasy XV was originally announced back in 2006 as Final Fantasy Versus XIII and has been renamed and reworked to become a new installment in the main series. The game is more of an action RPG than previous titles in the series, and is notable for featuring a darker and more realistic tone. Final Fantasy XV is based around the Fabula Nova Crystallis in-universe mythology, but the game's plot is not tied to previous entries.
The plot centers around the protagonist, Noctis, a prince of a place called Lucis. Lucis and nearby Niflheim have declared a truce between them that ends a war over crystals. Niflheim, instead of going through with the deal, decides to invade and start a new level of hellish attacks. It will be up to Noctis to escape and try to defeat the enemy forces in this Earth-like land.