The game takes place in the same universe as Bravely Default, occurring several years after the events of the first game. The game once again will entail a world of adventure, swords, and magic. A new character, Magnolia Arch, will appear in the game as one of the main protagonists. She is apparently from the world's moon, and the last of her kind after a demon attacks her homeland.
Source: Wikipedia, "Bravely Second: End Layer", available under the CC-BY-SA License.