"The Serpent's Chest" is a Mystery in Indiana Jones & The Great Circle that you can solve for great rewards, but this side quest has multiple steps to complete. Mysteries are treasure hunts, puzzles, or missions you find as you explore regions around the world. The Mystery revolving around the Serpent's Chest asks you to find ancient keys needed to unlock a box containing secrets from a time long past.

Those struggling to find "The Serpent's Chest" should look for this Mystery in Indiana Jones & TGC while they're in Sukhothai, a region unlocked later in the game's story. Exploring Sukhothai Village and its surrounding areas will help you discover the Mystery after a short time. Thankfully, the titular Serpent's Chest is not too difficult to locate once you enter this region.

How To Start The Serpent's Chest Mystery

Infiltrate The Right Place

When you arrive in Sukhothai Village, head to the Wat Chana Songkhram fast travel point to start looking for the Serpent's Chest. Go to the west of this location to discover Voss' Camp, an area crawling with enemies you may need to sneak past. Try to acquire the Royal Army Uniform within this camp to disguise yourself, allowing Indiana to walk among the soldiers here without antagonizing them.

You may already have a main quest objective tied to traveling to Voss' Camp when you're in Sukhothai Village. This quest, called "The Voss' Gold Stash" Field Network, will help you get enough money to buy the Rebreather in Indiana Jones & TGC. This device helps you breathe underwater, allowing you to reach new locations, including some places that will be crucial to solving the Serpent's Chest Mystery.

Before you enter Voss' Camp, you need to find an entrance to the location by climbing under a wall blocking off the area from the rest of the Sukhothai region.

Toward the southwest of the Camp, you can find a green tent after vaulting over a ruined wall. Inside the tent, you can find the Serpent's Chest, an unassuming container with a snake carved into the top of it. Next to the Chest, you can read a letter to start the Mystery and learn about what you have to do to open the Chest itself.

How To Solve The Serpent's Chest Mystery

Track Down Three Different Ancient Keys

When you find the Serpent's Chest, you can see that it is locked by three mechanisms that each have their own key slot. According to Voss' Letter, this Chest was discovered at a dig site in Gizeh, another region with plenty of side quests in Indiana Jones & TGC​​​​​. Through various research, Voss has discovered that the Chest can only be opened with three ancient keys, which are located in:

• The Vatican
• Gizeh
• Shanghai

The Letter has some clues regarding where each key might be found in every region, but you won't be sure until you travel. Since you have to Revisit old locations to uncover every key, this can be one of the longest Mysteries to complete in the game.

Where To Find The Vatican Ancient Key

The Ancient Key hidden in The Vatican area is found at the Excavation Site, a place you can reach by traveling through the Apostolic Palace. Both of these areas are restricted, so be careful traveling through either location. Once you arrive at the Escavation, head down the ladders there until you reach the main dig site underground.

The Apostolic Palace is where you can find the "Snake in the Garden" Mystery, which you can complete while searching for the Ancient Key to the Serpent's Chest.

From here, head right past the first main pillars in the dig site to travel deeper into an underground path. Keep going down until you come across a partially flooded room that you can swim through using the Rebreather. Swim along this pool until you discover a secret underwater age where a large log blocks a gate leading to a hidden area.

Move the log out of the way and swim upwards to find a secret, small pottery room. The ancient key will be inside a human skull directly below the largest pot in the center of the room, surrounded by other broken pots just ahead of where you arrive.

Where To Find The Gizeh Ancient Key

The Gizeh Ancient Key is located at the Khentkawes Excavation, a place you can reach by fast traveling. Unlike the one at the Vatican, this dig site is huge, but you still need to head into the central pit of it to start looking for the key. Before the elevator leading down to the main dig site, go past the right-most entrance from the generator powering the elevator, then turn right to start making your way up through the excavation work.

When you go up the stairs here, take a quick left to enter a room similarly filled with water like the one in the Vatican. Use Indiana's whip to travel across this space, then go right through the structures, crawling until you are on a small platform above some patrolling guards. Before reaching two crates, you'll see another path you can take to your right.

Along this path, you'll take the first right you see, which leads into a pool of water with rocks almost covering it entirely. Using the Rebreather, you can swim through this water and remove a log blocking a hole in the far wall. Getting through this wall leads to a small room where the Ancient Key is lying on the top of a pile of sand.

Where To Find The Shanghai Ancient Key

Shanghai is one of the smaller areas in Indiana Jones & TGC, making it easier to search for the Ancient Key. When you Revisit this place, you'll start along the rooftops where Indiana and Gina stole a plane. Go along the same path you did before when you were here earlier, jumping across rooftops until you reach an area close to the river.

Jump into the river when you see it​​​​​​, preferably at a height where you don't die from fall damage. From here, swim to the corner of the river and dive underwater, once again using the Rebreather as soon as you can. Doing this reveals yet another wood log blocking your path, so remove it to keep going forward.

There are no enemies to avoid when you Revisit Shanghai, but you can easily die here if you try to jump into the river from too high along the rooftops.

Traveling through the hole will quickly reveal a place where you can swim up for air. The Ancient Key is lying in the rubble of this small space, giving you the final piece to open the Serpent's Chest. Simply return to Sukhothai and Voss' Camp to open the treasure, earning you:

• Ancient Relic (Item) - 180 Adventure Points
• 250 Adventure Points

After you earn these Adventure Points, Indiana will add the Ancient Relic to his collection, which will likely be added to a museum someday. This also fully solves "The Serpent's Chest" Mystery as well, completing one of the lengthiest quests you can do in Indiana Jones & The Great Circle.