I think I understand it, and here is how I see it.
The first part we see (After diving through the branches and trees of the Pale Tree) is a land of clouds, with buildings slowly rising upwards, trying to reach the heavens, sending beams of energy into the sky. This, combined with the sandy, dusty color makes me think of only one thing.
The Crystal Desert.
Now those who didn’t play GW1, here’s how that plays in.
The Margonites once sailed on the Crystal Sea, which later became the Crystal Desert. While there, in an attempt to reach the gods, they built great towers and structures, higher and higher. Suffice to say, they failed. Their towers still remain in the Crystal Desert as a testament to their failure.
There’s more, however. In the center, a light, an object appears, only to fall downward into a cavern of crystal.
Purple crystal like this has been seen before… good old Kralky. And yes he is in the Crystal Desert, but he went there to deal with his traitorous lieutenant… Glint. We are told here that something relating to Glint is what we seek.
As we watch, the Crystal is shattered, and the glowing light destroyed. Glint’s death. But then it becomes surrounded by vines… lots and lots of vines. Such vines are seen wherever Moldy is… and in the Maguuma.
Tieing this in to what has been hinted at, that the Zephyrites are hiding something in the Maguuma and deal with Glint, this is what I believe.
What we are to do is find Glint’s Remains, or Glint’s Child, deep within the Maguuma, and attain the assistance of a traitorous Dragon Lieutenant, in order to defeat Mordremoth, if not more.