The adventure starts with Aunt Arctic telling the player that, although the important Island Codex has not been noticed by Herbert yet, it would be disastrous if he were to obtain it. She then tasks the player with hiding the codex, and not telling anyone where, including her. Aunt Arctic says she contacted an expert in hiding treasure to help, but since they could not make it, she tasks the player with seeking aid from Rockhopper instead, and hands over the codex. The player must go consult Rockhopper, who suggests burying treasure by a landmark, such as the buoy numbered 6, which is next the nearby lighthouse.
Then, the player has to dig at the red X, using a jackhammer. However, after digging on the spot, a treasure chest is uncovered instead, which excites Rockhopper, until he notices it is cursed. Rockhopper urges the player to cover it over, which must be done by digging on it again, and walk away. He then suggests trying to dig next to the buoy numbered 2 instead, which is on the southwest island at Coconut Cove. The player must go there and dig on another red X, but this time, a plate of stinky cheese is uncovered. Rockhopper notes this is where he hid his prized cheese, and thanks the player for completing another pirate adventure, but realizes that he is helping to bury treasure and not find it. The player must bury the cheese again, and Rockhopper nonchalantly says to bury the treasure in the ground by the Sea Caves.
By the entrance to the caves there is another red X, where the player must dig a hole, insert the codex, and cover it up. Rockhopper tells the player they did good work finding his cheese and burying the codex, although he is not aware of what the codex actually is. He also says to tell Aunt Arctic they are "even". After going back to Aunt Arctic, she thanks the player for hiding the codex, but hopes it can be retrieved soon, although it is too much of a risk for Herbert to have it. She then mentions that a plan of attack against Herbert will be put into effect soon. The player then receives the 3 fabrics, 3 decals, blueprint for Agent Armor, 100 coins, and 200 Aunt Arctic XP.
Given to the player by Aunt Arctic in order to bury it and tell nobody so that Herbert will never be able to obtain it. It is eventually buried on the beach in Coconut Cove, near the entrance to the Sea Caves.
Before this adventure was released and the Island Codex was first physically seen, Aunt Arctic mentions it in Ep. 5 - A Cursory Look where she says that the codex contains a recipe to cure curses, which she gives the player to use to cure Rockhopper of his curse. Additionally, one of the messages that can appear when first loading the Club Penguin Island app is "Translating Island Codex…"
On November 1, 2017, the XP rewarded for completing this adventure was changed from 150 to 60.
In the 1.13.0 update, the reward was changed again, from 60 to 200.
In the 1.9.0 update, the coin reward was changed from 50 to 100.
Names in other languages
Enterrando o Tesouro
Proteja do Herbert o misterioso Códex da Ilha.
Dissimulation de trésor
Mets le précieux Codex de l'île à l'abri d'Herbert.
Enterrando un tesoro
Protege el misterioso Códex de la Isla de Herbert.