Finding a Moon Lantern makes travelling through the Shadow-Cursed Lands in Baldur's Gate 3 much easier, so you'll want to get your hands on one as early as possible. Thankfully, there's a way to grab one pretty quickly and get permanent immunity to the Shadow Curse, though naturally, you'll need to make a few choices beforehand.
Until you get your hands on a Moon Lantern, you'll need to use a light source to hold off the curse. A regular torch works fine, as does any light-producing cantrip or weapon, such as the Blood of Lathander, but it's a lot less hassle once you no longer need to worry about fending off the curse. Here's where to get a Baldur's Gate 3 Moon Lantern, or fix a broken one, so you can traverse the Shadow-Cursed Lands with ease.
Baldur's Gate 3 Moon Lantern: Where to get one
If you travel to the Shadow-Cursed Lands via the Underdark, you should pick up a working Moon Lantern from Nere, but if you somehow missed that, or you arrived in the Act 2 area via the Mountain Pass, I'll explain where to pick up this handy light source.
From the Mountain Pass entrance, you should keep heading west until you find a tree arched over the road and a couple of broken wooden buildings off to the side. This is a good point to save as you'll have to win a couple of rolls in a moment. If you keep heading this way, you'll see a spider man (no, not that one) and his minions patrolling the road, and he's carrying a Moon Lantern.
You can call to him using Minthara's Spider Lyre, which you get for destroying the Emerald Grove or looting it from her body, or get closer and a cutscene will kick in.
You can call to him using Minthara's Spider Lyre, which you get for destroying the Emerald Grove or looting it from her body, or get closer and a cutscene will kick in.
Naturally, one of them will spot you hiding in one of the buildings, so Clear your throat to make yourself known, then tell them that The Absolute protected me. I chose Deception as my next option, which forces a Charisma check. If you pass they'll argue, but hand over the Moon Lantern so tell them they can go now. More arguments give you another choice—go with Deception again—then you'll hear them dying in the shadows.
You can now pick up the Moon Lantern. You'll spot something inside and be presented with a final choice. Release the pixie and ask her to help when given the option and she'll grant you her blessing which is as good as any Moon Lantern for protecting you in the Shadow-Cursed Lands. The blessing only lasts until the next long rest so you'll need to reuse the Filligreed Feywild Bell item which can now be found inside your inventory.
How to fix a Broken Moon Lantern
You might find a broken Moon Lantern while traversing the Shadow-Cursed Lands. While it is possible to fix one, you're likely to already have one way before you reach the Moonrise Towers so there's really no need to do it here.
If you feel like you need another, there's a secret room in Balthazar's study on the first floor of Moonrise Towers. To reach it, activate the top right row of protruding books in the bookcase on the west wall then take a heart from one of the corpses and insert it into the receptacle with the skull next to it to reveal a hidden door.
Inside this room, you'll find many broken Moon Lanterns and other paraphernalia. You can use the ritual circle here to fix the Moon Lantern with a dead pixie, which you'll find on the nearby table.