Upon entering octam, enter the left most house, and pick up a "Swift Water" on hidden treasyre chest, on the upper right corner.
Now exit the house and take a "Healing Bloom" on the center of 2 bushes, on the right side of the house.
Now exit, and go right to the fartest right most house, and take a "Speed Elixir" on the cupboard.
Read all of the stone book, and a secret door will be opened, where you should get down, and meet our side character, "CARA".
According to Cara, Octam's people has leave octam and go underground with the elevator nearby, but it has been locked for safety precaution.
Cara also told Vahn that the "Star Pearl" they have looking for has been handed over to our old friend Zalan in Jeremy.
Now that we know where the star pearl is, head back to jeremy. You can head back manually by walking to level up your characters along the way, but i'l just use "Door of light" and "Door of wind" to reach jeremy.
In Jeremy, head to Zalan, and he'll give you the "Star Pearl" for free. Now that you have the star pearl, lets head to the "GATE OF SHADOW".
Use your "Door of wind" back to OCTAM, and head "North East" from Octam to Reach the "Gate of Shadow".