The Horn of Jurgen Windcaller

After completing "The Way of the Voice", Arngeir sends the Dragonborn to Ustengrav, tasked with recovering the Horn of Jurgen Windcaller. Arriving to find it stolen, the Dragonborn must discover its whereabouts.

Within the tomb, the "Become Ethereal" shout is learned. Obstacles in this location include Draugr and hostile Mages.

Background
After demonstrating my ability to learn the Words of Power and to Shout, the Greybeard Arngeir has sent me on a final trial - retrieving the Horn of Jurgen Windcaller from his tomb in Ustengrav, a burial mound in the marshes of Hjaalmarch.

Walkthrough
First, travel to Ustengrav, which is just northeast of Morthal. Inside are Mages, Necromancers, Draugr, and Conjurers fighting each other. There are four things of note in this tomb: a hard-to-reach room, a word of power for the Shout Become Ethereal, a puzzle room, and a note.

The Shout
The hard-to-reach room is in Ustengrav Depths. In there, the large pillars have collapsed paths along them. Find the rock closest to the first pillar and jump across to it. Whirlwind Sprint is needed to reach the last two pillars. At the end is a room with a dead Draugr, a Soul Gem, and a chest.

There is a waterfall back in the main cavern on the north side and a path that leads down to it. A Word Wall for the Shout Become Ethereal is next to it. There is a level dependent Draugr slumbering in a small cave behind the waterfall itself. There is also a chest there.

The puzzle room
There is a puzzle room with three stones that activate three timed doors, use Whirlwind Sprint within distance of the two farthest stones and then immediately sprint through the gates. The stones are proximity sensitive, but only two of the three can be activated from one place, nor will a waiting follower keep them activated. Activate the two furthest from the gates. The third activates and open its gate as it is passed using Whirlwind Sprint. The Dragonborn can sprint to the third stone and then use Whirlwind. Once all of the gates are passed, they remain open, allowing followers to catch up unscathed.

The flaming floor
After going through the catacomb-like room, there is a room with a large number of pressure-triggered fire traps on the floor. The curved diamond shapes in the center of each tile are different shades of gray. The lighter tiles are safe to step on, while the darker ones will trigger flame traps. Another solution, aside from using Whirlwind Sprint, is to use the Become Ethereal shout, which will render the flames harmless for as long as the shout is in effect. After passing the pressure plates, there may be one or two regular Frostbite Spiders and one Giant Frostbite Spider. It is also possible to walk on the rocky sides rather than the pressure tiles for most of the trapped hall. Another solution is to shoot the tiles with a spell such as Firebolt or Ice Spike. Flames/Sparks, etc. don't work. The impact of a bolt or spike is enough to set off the trap if it's not a safe tile. (NOTE: the sneak ability light foot makes getting through easy, as you will not trigger the traps)

After making it past the spiders, there is a doorway blocked by spider webs, which can be cut with a sword. Behind is a wooden door, which leads to a gate activated by a chain. This leads to a room where four statues rise out of the water.

The Unfortunate News
Unfortunately, the horn has been stolen and replaced with a note, Mysterious Note. The note is in the hand of the deceased Jurgen Windcaller, where the horn should be. The note must be actively taken and read, even though the quest system tells its contents when it announces that the Horn of Jurgen Windcaller quest failed.

The note sends the Dragonborn to the Sleeping Giant Inn in Riverwood. Talk to Delphine and ask to rent the attic room. She will say that they don't have an attic room, but to take the room on the left. Go into the room. If Delphine does not immediately enter the room, sleep or wait for a few hours. Delphine will then be there. After the conversation, follow her and she will give the Dragonborn the horn. She will then ask that she be joined on a quest to be proved a Dragonborn. This begins the A Blade in the Dark quest.

Return to the Greybeards
Travel back to High Hrothgar and present the horn to Arngeir. The Greybeards will gather in the main hall where Wulfgar will teach the final word of the shout Unrelenting Force.

Following this the Greybeards will perform a ritual that formally recognizes the Dragonborn as Dovahkiin. The Greybeards shout at once in Dragon language the following:

"Long has the Storm Crown Languished with no worthy brow to sit upon. By our breath we bestow it now to you in the name of Kyne, in the name of Shor, and in the name of Atmora of old. You are Ysmir now, the Dragon of the North. Hearken to it."

Once the ritual is completed, the quest is completed.

Trivia

 * If the Dragonborn does not have any gold when asking to rent the attic room from Delphine, the room can be rented for free.
 * After completing the quest, the Dragonborn can return to Ustengrav and activate the altar where the note was to return the horn and get a free Dragon Soul.
 * After presenting the horn to Arngeir, when he performs the ritual that formally recognizes the Dovahkiin as a Dragonborn, a follower that may be there will not die, even hearing the voices of the Greybeards, knowing that even a whisper could kill anyone who is not prepared.
 * If you visit Ustengrav before starting the quest, it will be blocked by a cave-in. If you use the console to reach the altar, the horn and note are not present.
 * If the player has installed the The Elder Scrolls V: Dragonborn, the first quest of the add-on is available upon receiving this quest.

Bugs

 * If the Dragonborn skips entering the attic room and talks to Delphine outside, the Dragonborn will not receive the The Horn of Jurgen Windcaller and will not be able to continue on with the rest of the main storyline.
 * Solution: Enter this command in the console: setstage . Doing so will instantly complete the quest.
 * There is a chance that the shout word Dah will be written on the floor and not be able to be learned.

Das Horn von Jurgen Windrufer (Quest) Cuerno de Jurgen Llamador del Viento Il Corno di Jurgen Windcaller Рог Юргена (Квест) De Hoorn van Jurgen Windroeper