Is a seque to XIII and contiunes the story from fourth. Personally, it was very fun, you can fight alongside with monster you've captured in battle even Boss battle! The graphic is rendered into pure HD, every pixle being used. Highly recommened this, but you may end up keeping it so have your wallet ready!
A lot of people act as if this game is terrible, but I find it to be excellent in its graphics and the battle system is much better than it was in my opinion. I feel the story line is good....maybe just a bit lazy.