The adventure starts with the player talking to Rockhopper, who had a stroke of inspiration, and thinks the three plaque copies made during the previous adventure fit together to make a picture. The player must then assemble the copies on top of each other, which form an image of a penguin swimming into the mouth of a large oyster, then throwing a pearl into a volcano, and then inserting it into a spiral device. Rockhopper exclaims that these are instructions to find the treasure of Penglantis, and that the player should go find a giant oyster in the Sea Caves in order to get a giant pearl. The player must then go to the caves, and swim down into the Glow Grotto, where the giant oyster is. Upon reaching it, it spits out a giant pearl.
Rockhopper then tells the player to throw it into the volcano at Coconut Cove. Upon going to the shark teeth and throwing it, the volcano shakes and erupts, blasting the pearl to the hill at the Beacon Boardwalk, and turning the pearl black in the process. The last step is to find a stone with a spiral shape, and Rockhopper suggests looking around the ruins on the eastern side of the Coconut Cove. The spiral is on a stone wall surrounding the east edge of the area, and the player starts to insert it, but Rockhopper stops this at the last second. He says he is not ready for the treasures, and that he needs to "clear space in the Migrator's hold", "brush his beard", and "write an acceptance speech" before the pearl is to be inserted. He then requests the player wait before discovering the find of his life. The adventure is then complete, and the player receives the blueprints for Something In Me Aye and Bushy Beard, 100 coins, and 150 Rockhopper XP.
Received from Rockhopper after the plaque copies from the previous adventure are pieced together and he tells the player to find a giant pearl. They depict a penguin grabbing a pearl from an oyster, then throwing the pearl into a volcano to make it colored black, and then inserting the black pearl in a spiral device.
Obtained from the giant oyster in the Glow Grotto of The Sea Caves. It must then be thrown into the volcano at Coconut Cove, which singes it a black color.
After the pearl turns black, it must be inserted into the device with a spiral pattern at the ruins in Coconut Cove.
On November 1, 2017, the XP rewarded for completing this adventure was changed from 140 to 60.
In the 1.13.0 update, the reward was changed again, from 60 to 150.
In the 1.9.0 update, the coin reward was changed from 50 to 100.