We haven't had much news on the game as of yet, mostly due to a lack of official word from Nintendo and Square on the game's contents. Now we know, for example, that there are over 180 magic gems that players can use to customize their characters.
Turns out, in the game world, 10 years before the start of the game for the player, a great catastrophe has struck the land of Illusia and monsters have taken over the land. This, in turn, causes the Mana Tree to become corrupt with its own power and mysterious Mana pillars to have erected across the world. With the aid of the Sword of Mana, the player must free the locked guardian spirit within each pillar and restore Illusia back to its original status.
The main characters of the game are Ferrik, who was saved as a child by a nameless swordsman and has spent the entirety of his saved life trying to become a great swordsman himself. He lost his parents and older sister during the catastrophe. Tess is a more scholarly type, spending all of her time studying the Mana Tree and its Mana Goddess. Poppen is a magician from the desert of Jadd. Tamber is a young dancer who lost her brother and parents during the catastrophe. Finally, Wanderer is an outcast of the niccolos race and is described as loyal and compassionate.