The Trailer For Frozen 2 Left Us With a LOT of Questions — Here Are Our Theories

A magical fire dances through the forest and startles people into running away. It looks like the people in question are the folks of Arendelle, who can be seen in the background when Elsa and Anna are talking to Pabbie in the rock troll clearing. The most likely conclusion to draw here is that sometime after Pabbie relays his message to Elsa about her needing to head north, something or someone causes the pink fire to light up the forest and scare away the people of Arendelle.