You take a close look at the map and look at the four main islands you had to visit earlier in your quest. After a moment of pondering, you connect the dots and discovered that it makes an X right over where the Temple Grounds Cloud station is. You should go there and see what you can find.
Search around the area of the northeastern Temple Grounds cloud station for clues.
Search for clues that might lead to the lost treasure. (in Tenebrous Tangle)
Return to Bilgeron Cogsworth on the Temple Grounds.
Quest Rewards above are only the guaranteed XP, faction, and coin rewarded for this quest. Status points and rewards limited by class, race, alignment, etc. are unavailable.