In the aftermath of the Snow Queen's spell, portals were opened up all over Storybrooke bringing in people from realms far and wide - across all universes (even the alternate ones). In a desperate attempt to protect the world at large from the influx of these newcomers, Regina sealed off Storybrooke permanently, making it impossible for anyone to leave the magical town.
You and me. Let's talk. You owe me that much and I owe hearing you out. But I want to know the truth--and I'm sorry, but I just don't think you're giving it all to me.