Baldur’s Gate 3 | Defiled Temple Moon Plate Puzzle Guide (How to Get Into the Underdark)

Baldur’s Gate 3 is full of little puzzles, riddles and mysteries for players to explore and solve. One puzzle players may find themselves stumped on early in the game is the moon plate puzzle in the Defiled Temple of Selune. If you manage to complete this puzzle and solve it correctly, you’ll unlock one of the few direct lines between the surface and the Underdark, an extremely dangerous (and bountiful) region full of new quests to complete, items to unearth and secrets to find. The Underdark is also one of the primary routes through the main story, making it a must-unlock priority for basically any player.

Here’s how to solve the Defiled Temple moon puzzle and easily get into the Underdark in Baldur’s Gate 3. 

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1. Baldur’s Gate 3 | How to Change Classes, Multiclass and Respec
2. How to Get Permanent See Invisibility Early in Baldur’s Gate 3 (Volo’s Ersatz Eye Guide)

How to Get Into the Defiled Temple

Connected to the Shattered Sanctum, the Defiled Temple is a somewhat hidden area in Baldur’s Gate 3. You can reach this location by following the main story of Act 1 after arriving in the Goblin Encampment. There are several potential entrances to the Defiled Temple, with some being far easier than others.

The easiest way in is by interacting with Priestess Gut, a True Soul Goblin. She’s handing out Brands to the Absolute in the main chamber of the Shattered Sanctum. After approaching Gut, you can refuse her Brand, revealing that you are also infested with an Illithid tadpole. She’s very excited to have found another chosen one and says that she may be able to help you with whatever affliction you have. 

After that, she’ll usher you away to a private section of the Sanctum so she can perform more psychic tests. These tests reveal the parasite to Gut but, strangely, she believes she isn’t infected and is just divinely chosen. At this point, you’ll be knocked out by Gut (who wishes to see you transform into a Mind Flayer) and taken directly to the Defiled Temple via a door in Gut’s room. After the events revolving around Gut concludes, you can wander the space as much as you like.

The Easy Way In

The other two methods are a bit trickier but still possible to undertake. The first way in is via the Spider Pit, an area below the Shattered Sanctum locked by an iron gate. Two hungry Giant Spiders will be waiting to greet you should you open the gate and venture inside. From there, you can either kill them or direct them to feast on the nearby Goblins as a distraction. With the Spiders out of the way, you should easily find the Defiled Temple entrance close at hand. 

The other way is through the Zhentarim storage area. Right next to Priestess Gut’s room in the Shattered Sanctum is a small group of Zhentarim merchants, with one trader and two guards watching over a specific room. You can try and blag your way through or just kill them all (be warned, though, that this may have ramifications for other Zhentarim down the road) but once you’re in there, you should spy a crack in the way behind all the treasure and wine. Unfortunately, only small creatures such as Halflings and Gnomes can enter, so get your Shapeshift Spells ready if you plan on this route.

Moon Plate Puzzle Solution in Baldur’s Gate III

In the southern reaches of the Defield Temple, just past the Rocky Crevase where you can enter via the Zhentarim Store Room, is the desolate main chamber. On the floor of the temple are four circular plates that cross over one another. Four slots on each plate are either left empty or filled with a white moon. Your goal for this puzzle is to rotate the plates in such a way that the moons end up in the correct place, opening a secret door at the back of the room should you do it correctly.

The solution to the puzzle can be found in a few places around the Shattered Sanctum, displayed on walls in the form of a mural. In short, you need to leave the bottom plate (the one being hit by direct sunlight) completely empty of moons. For a more in-depth explanation, here’s the correct alignment for the plates:

• Top Plate: Complete fill in all moons.
• Left Plate: Fill in every moon aside from the bottom right. 
• Right Plate: Fill in every moon aside from the bottom left.
• Bottom Plate: Leave complete blank with no moons filled in. 

Defiled Temple Underdark Entrance

If you manage to complete the puzzle successfully, a door will open at the back of the chamber. This is your way into the Underdark: a terrifying place full of horrors unknown to the surface races. Opening the door will also progress the Find the Nightsong sidequest and the Moonrise Towers main quest (if you received that from Halsin).

Once you finally touch down on Underdark soil, you’ll find yourself in the Underdark Selunite Outpost. Pillage the area for supplies, grab everything not nailed down and then make sure to grab the Waypoint marker before proceeding. From this point on, you can explore the terrors of the Underdark to your heart’s content. Just be wary of the danger lurking right outside the outpost’s gates. 

Into the Yawning Dark

That was how to complete the Defiled Temple moon puzzle and enter the Underdark in Baldur’s Gate 3.