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.
Hey... this is gonna sound really weird and sudden but... would you mind grabbing lunch or something with me? You're one of the few people I feel isn't judging me right now, and I could use a friend.