Although The Division isn't officially releasing until tomorrow, there are people who have already gotten their hands on the game. And while the servers aren't available yet, at least in some areas, curious fans have begun datamining the game files for any hints about the game's contents and storylines.
Users on Reddit have dug deep, seemingly discovering that the full version of the game includes a total of 26 story missions. By comparison, the recent open beta of the game included two, wherein the player was tasked with rescuing key staff from a makeshift field hospital and an underground construction site.
Note that 26 missions doesn't include side quests or other activities, of which the game appears to have plenty. The mined data also includes info on guns and other gear available in the game, voice lines and other story spoilers, so peruse Reddit and other forums at your own risk.