Storybrooke AU

Storybrooke AU is a fairly new AU (Alternate Universe) within the Rise of the Brave Tangled Dragons fandom. In the AU, Rapunzel, Merida, Hiccup and Jack Frost were sent from the Enchanted Forest, a world of fairy tale characters, and sent to the small town of Storybrooke, Maine.

About this AU
The world of Once Upon a Time has been a popular universe for fans to use for crossovers. Storybrooke is the perfect location for the Big Four to interact because of a number of reasons: it is a location for a multitude of fairy tale worlds where magic and science-fiction-based elements can be found, famous characters and aspects of folklore and literature (like the Guardians, the Boogieman, Rapunzel, the Snow Queen, dragons, Count Dracula, etc.) would be able to coexist and can allow a contrast between these magical worlds and our modern world. Because of this, this AU can simultaniously act as Modern AU and Fairy Tale AU.

Some aspects of the fandom take place in a modern world (Rise of the Guardians and Hotel Transylvania) while others happen in locations in an earlier, more magical point in history (Tangled and Brave) or in worlds surreal beyond realism (The Lorax and  The Croods), so the idea of different realms sharing the same universe as the real world like in the show would make sense.

In the original show, there already exists an incarnation of Rapunzel, but fanfic writers prefer to use Rapunzel Corona instead due to her more developed and proactive character.