In the second act of Baldur's Gate 3, Halsin will assign you a task to find a creature that hinders the removal of the parasite. The player is offered several paths: tunnels in the dungeon — which were available in the early version, as well as the mountain pass and the Grimforge dungeon, which were added in the release part. In this guide, we'll talk about how to go through the already classic tunnels, about the safer mountain pass, and about the aggressive option, where you'll need to find a moon lantern to explore the locations on your own.
Return to the goblin camp and kill all the enemies that attack you. To increase your chances of victory, you can hire ogres from the nearby destroyed village to help you. Then, ask Halsin for directions to the dungeon. In the dialogue, he should mention a tunnel located in the temple of Selûne.
To reach the moon towers, you need to return to the ruined sanctuary and visit the room with the gilded door in the corner. Entering it, you'll encounter a giant named Polma, who you need to defeat to proceed.
You can try persuasion, intimidation, or deception, but you will need to pass a difficulty class check of 22. In case of failure, a battle will start, after which you should search the room for the priestess's diary, which contains a hint for solving the next puzzle. Next, entering the eastern room, a perception check is performed to notice the moving painted tiles in the center of the room.
An interesting puzzle can be found in the northern hall of the desecrated temple. By studying the priestess's diary, you get a hint: «Intersecting circles will align the full moons with the stars, while casting down the darkness where it belongs». Rotate the tiles so that the symbols match the screenshot below, or simply press the lever located near the door. It's important to remember that if you solve the puzzle and then use the lever, the required door will close again.
If the lever is locked, use a set of thieves' tools to pick the lock on the lever, passing a lockpicking difficulty class of 15, and open the passage. Continue moving through the linear level until you reach a wooden ladder that will lead you to the Selûnite Outpost.
Avoid contact with mushrooms and defeat the two clumsy minotaurs who will try to knock you down during the tactical phase. Further into the location, you can obtain a side quest that will improve your relationship with your companion Gale. Afterwards, talk to the two merchants nearby to receive two more quests. Blurg can assist with the mind flayer parasite in the player's head.
Head south from the merchants to find Glut. This myconid will join the main group and will lure the duergar to your side, significantly reducing the number of battles.
You will complete most of the side quests once you finish fighting the duergar. To move to the next location, you need to board a ship, but remember to save your game as you won't be able to return to this area.
To safely navigate this location, make sure you have the Spider's Lute, which can be obtained from Minthara in several cases:
Note: Choosing this option may cause you to miss several useful quests, including the opportunity to improve your relationship with your companion Gale.
Head northwest from the deserted village until you encounter bandits. After defeating them, you will unlock additional quests and access to a new location.
Use the map to quickly find the entrance to the required location. The area you find yourself in is scarce in resources, so there's no need to linger.
To advance further, you will need a guide in the form of Drow. Try to stay in the light near your new ally. Ahead, you will face several battles that pose no significant threat. Simply continue moving and protect the caravan. In the end, you will be able to reach the Moon Towers by taking a relatively quick and safe path.
If you don't have the Spider's Lute or wish to navigate all locations on your own, there is a way to do so. In the abandoned refuge, head southeast from the Grimforge dungeon to free and battle Nere and his team.
After victory, you will receive a lamp, and a gnome will approach you, heading towards the Moon Towers. Talking to him can provide a lot of useful information, send him to your camp, and reveal a marker indicating the further path.
Once in the dungeon, move to the left until you find a passage to the lands tainted by shadow.
After the cutscene, you'll be prompted to surround yourself with light, or the squad will start taking damage. Use the evocation focus «Light» on all heroes or use Nere's lamp. Your task here is to find the lost squad in the darkness and fight the shadows. After that, follow the marker to the lower left corner of the map.
The area around the Moon Towers is surrounded by a dark curse. The only safe way to explore this zone is with a moon lantern, as the light from spells and torches will not be sufficient. While in this area, you will periodically take damage, meaning you can reach the entrance to the Moon Towers simply by running across the bridge and passing through customs. Just don't forget to replenish your health potion supply.
If you reach the guards without a Drow, they, along with the wraiths, will be aggressively disposed. It's essential to pick up a parasite from one of the corpses, which you can examine and open your mind to in the larva.
After the cutscene with the goblins, go up the stairs and look into the open door on the right. To open the next door, look for a key from one of the guards, break it with magic, or use a thief's kit. In the room that opens, the moon lantern will be on the stand.