Right now Fire Emblem Fates ( Fire Emblem If in Japan) comes in two varieties: Birthright and Conquest , each telling a different story with different characters. In July, a third version will be available in Japanese territories as an additional DLC scenario. This scenario will have just as much story content as Fire Emblem: Awakening did, and is reported to have you facing a different group rather than the Black or White Kingdom.
No matter which version you play, you will be able to unlock the third route as DLC for 2,000 yen by choosing the “open a new future” option on the main menu.
The third scenario is releasing in Japan in July and in the West in 2016 after the initial Fire Emblem Fates launch.
Source: Siliconera