When you first get to the desert area in Genshin Impact’s Sumeru, you won’t have access to the “Red Desert Threshold” domain right away.
No matter how you may look for it, the map will tell you that the domain is below you, though there’s no way to get to it. In order to access the “Red Desert Threshold” domain, you’ll need to start the world quest line “Golden Slumber.” You can start it by talking to the NPC below in Aaru Village.
Graphic: Julia Lee/Polygon | Source images: Hoyoverse
Once you start the quest, you can follow the navigation to head to a huge pit that opens in the ground. The “Red Desert Threshold” domain is in this pit, right as you jump in.
This domain can only be cleared once for rewards, and gives you loot like Primogems, Dendro Sigils, and various upgrade materials. Most importantly, the domain will serve as a convenient place to teleport to get into the new hole in the ground.