- Attempt to retrieve the Horn of Jurgen Windcaller from Ustengrav.
- Meet with whoever took the horn in Riverwood.
- Return the horn to Arngeir.
- Learn the Word of Power from Wulfgar.
- Receive the Greybeards' greeting.
After completing The Way of the Voice, Arngeir will assign you one last task to prove you are Dragonborn: retrieve the Horn of Jurgen Windcaller, so named after one of the heroes of old. The Horn is located in the ruin of Ustengrav, which Arngeir marks on your map. The simplest way to reach Ustengrav is by taking a carriage to the town of Morthal, then travelling the marshes on foot. The ruins are due northeast of the town. If you wish to walk, the fastest route from the Throat of the World is to pass through the fields around Whiterun and follow the route northwest directly through Labyrinthian. However there are Frost Trolls in the ruins of Labirynthian. When you arrive at the Ustengrav ruins, you'll encounter some bandits engaged in combat with mages. Since both groups are hostile, you'll likely have to deal with survivors unless you can sneak past them.
The first level of the ruin is fairly straightforward, with a few mages and draugr to deal with. Sneaking and following the mages deeper into the ruin allows the draugr to pick them off as well as vice versa, resulting in fewer enemies to contend with. Pick off any remaining draugr (most will be dead on arrival) and descend into the second zone of the ruin.
Upon entering Ustengrav Depths, you can see a sparsely forested chasm with a waterfall and a bridge far below. To descend, navigate the winding path through the rest of the ruin. You will deal with several draugr and a fire trap along the way. The outdoor area itself hosts several skeleton patrols, both on the ground by the bridge and in the somewhat higher level with the wood barricade. These can easily be shot down with your bow. In the room with the tall pillars a skeleton seated on a throne will come to life at your approach. If you jump to the rocks on the left at the top of the ramp leading down into the room, then jump and Whirlwind Sprint between the circular platforms on the pillars, you will reach a secret room with a soul gem and a chest.
Near the bottom of the waterfall is a Word Wall with a Word for the Become Ethereal shout. It can be seen from the bridge and is reachable by a small path carved from the side of the cave wall. Behind the waterfall is a hidden area containing a draugr and small amounts of loot. The Horn, however, lies on the other side of the bridge. After gaining the Word, return up the path and cross the bridge.
Across the bridge you may encounter a lone skeleton who is easily dispatched. The main attraction here are the three outcrops of rock carved with runes and the gated tunnel you must traverse to continue. Each of the rocks glows red at your approach and lifts one of the gates barring passage through the tunnel. If you have unlocked both words of Whirlwind Sprint, using it to sprint through the stones opens the gates long enough to walk through them all. Once you are clear, the gates will remain fully open, allowing any followers to catch up. With only one word of the shout learned, getting all three gates to stay open long enough is trickier. Some suggestions are to start at the rock closest to the bridge, sprint by each of them until you get close to the tunnel entrance, and from there use Whirlwind Sprint to clear all the gates at once. Or you may find it easier to stand in front of the first rock, use Whirlwind Sprint, and then run through the rest of the tunnel. It may also be possible to use the shout twice in quick succession. This does not happen elsewhere in the game (tested twice on PC). If you become trapped between gates inside the tunnel, you will find pull chains that will allow you to return to the rocks and try again.
The floors of the next few chambers are covered with fire traps. There are two frostbite spiders on the cobwebbed arch. It's possible to avoid the traps by sticking to the walls, and you can even use them to help kill the spiders if you lure them into the fire-trapped area. The traps have a slightly delayed reaction to your passing over them, so if you're on your own you can get away with just sprinting forward and you won't be badly burned. There are a few rocky ledges and, in the next room, a raised dais - these don't have firetraps on them so you can safely stand on them. This room contains a more powerful giant spider hiding in the ceiling which may spawn babies. The giant spider will attempt an ambush when you get close. Using resist poison and resist frost potions may help you survive them.
If you have a follower, dealing with the fire traps can become complicated. Even if you are standing in safety, followers may come to a halt on the fire trap and stand there until they burn to death. Because they exert a continuous-damage effect, these traps will actually permanently kill your followers if you aren't careful. If you've told your follower to wait in a safe place, and they run onto the traps to engage an enemy, they will get stuck there taking damage, unable to be told to follow you again. If this doesn't kill them, they will remain behind when you leave. However, after three days the follower will become tired of waiting and return to their usual hangout.
After dispatching the spiders, cut or blast through the cobwebs covering the tunnel (there are two sets). If you are an Alchemist you may wish to make sure you have picked up all three Spider Eggs on offer from the egg sacs in the spider nest, but otherwise go right ahead and enter the final chamber.
As you make your way through the final room, four Nordic dragon carvings rise out of pools of water. These have no effect. On the pedestal which you would expect to find the Horn, you will instead find a mysterious note addressed to "the Dragonborn." It states that the Horn has been removed and requests that you meet the note's anonymous author by renting an attic room at the Sleeping Giant Inn in Riverwood.
Having failed the task, do as the note says and go to Riverwood. When you speak to Delphine, about renting the appropriate room, she will tell you that there is no attic room, but that you can take the one on the left. Delphine follows you, reveals that she was the one who took the Horn, and gives the Horn to you. She asks to speak privately, and you follow her to the room you usually rent. Delphine opens the wardrobe door, revealing a secret room beneath the inn. In this room, she tells you that "her organization" has been looking for someone like you, and that she took the horn in order to get your attention. This exchange with her begins the quest A Blade in the Dark, and is detailed further on that page. After discoursing with her, you are free to return the Horn to High Hrothgar and complete the quest.
Return to High Hrothgar with the Horn and present it to Arngeir, completing the task he originally gave you. (Additionally, you can return to Ustengrav and receive another reward; see Notes.) Arngeir will go to the main hall, where the other Greybeards are assembled, and Wulfgar will teach you the last word to the Unrelenting Force Shout. You will then be frozen where you stand to learn the Word, and all the Greybeards will Speak to you at once in Dragon Tongue, formally recognizing you as Dragonborn. (You are not harmed by this exchange.) This completes the quest, and from now on High Hrothgar is open to you.
