Online:The Shackled Guardian

Quick Walkthrough
# Talk to Narir.
# Collect lost notes, and save the captive delvers.
# Find and talk to Kireth Vanos.
# Investigate Taarengrav Barrow.
# Find Daneras in the barrow.
# Solve the puzzle.
# Disrupt the ritual.
# Talk to Valdur.

Detailed Walkthrough
When you approach Taarengrav, you see Raynor Vanos, a Dunmer, running toward you. His sister, Kireth, led a team to investigate the barrow. They were almost inside, when the Worm Cultists attacked. He ran straight outside, leaving his sister and the others behind. He says the site has been completely overrun. The real reason Raynor is out here is to get help; you need to talk to Narir, the leader of the small contingent of Companions that arrived on the scene.

Narir is just around the corner, at the small camp. The Companions tracked the cultists from Stony Basin and arrived just before they did. He is not enthusiastic about his men's or the dig team's chances of survival should the cultists attack again. However, the dig team did find a puzzle in the ruin. They haven't solved it, but they were able to gather some clues. Unfortunately, the cultists killed them to get their notes. The puzzle must hold the key to what they are looking for, so it is up to you to save the team and their notes. 

If you ask him for more information about the puzzle, he replies that it is a series of doors with runes above them. If you ask about the runes, he reveals that he is worried about Kireth, and the runes mentioned a guardian. You can also ask him about the site itself. It is a dragon mound, where the dragon cult used to perform rituals and other "horrible things," at least if the old stories are to be trusted. The dragon cult members still walk the depths of the site, guarding ancient secrets. 

Gathering Notes
There are eight notes to find and three captured members of the dig team. You need to defeat cultists to gather the notes. You'll know the delvers when you see a bright blue rune and a group of Worm Cultists. You need to defeat the cultists to free the delver. The first delver gives you three notes, the next gives you two, and the third tells you that Kireth is behind the dragon mound as they run off. Defeat some more cultists to get the final notes.

Kireth is southwest of the Taarengrav icon on the map, tied up inside a tent. 
:''"I heard what the Worm Cult is after. They're searching the Rift for the spirits of Ysgramor's legendary Five Hundred Companions. They intend to enslave those spirits and bind them to the giant Sinmur."
:And there's a spirit here?
:"I believe the ruins contain the burial vault of Valdur, one of Ysgramor's Companions. Those pages you've collected? They're the clue to getting inside."''

You promise to talk care of the cult, and she asks you to find her apprentice, Daneras in the vault. Both of you need to find a way into the tomb and stop the cult. She runs off after you untie her, and you make your way to Taarengrav Barrow. Be careful not to jump straight down into the hole, as you do take fall damage.

Into the Barrow
Upon entering, you see the spirit of Valdur. Talk to him, and he warns you to make your way through the barrow quickly. He hints that you may be needed elsewhere and says that the cultists are already casting their spells on his body. You need to solve the puzzle and stop them.

Continue down the stairs, noting the door on the right (your quick exit out), and defeating more Worm Cultists and draugr. At the T, go right, although you can loot the left side for miscellaneous items from urns and trunks. You'll see a fire trap and a door deeper into the barrow. 

This door leads to a large, partially flooded room with draugr. Go through the southern arch, past more fire traps, to see Valor's spirit appear to you again, this time captured and pleading with you to "stop them." 

You are now in another large room with lots of draugr. Get on the raised wooden ledges leading to the north, and enter another metal door.

Inside, you see Valor's spirit and Daneras, sitting on the ground to the left. At first he thinks you are a hallucination from his "gut wound" and blood loss. You need to read the delver notes to decipher the puzzle.

The Door Puzzle
Read the Delver Notes. The clues are "deep sea swimmer," then "watch on the wing," and finally "the venom pulses." This means you need to "follow" the Whale, Eagle, then Snake. 

First, though you need to talk to Valdur. The cultists are tearing his soul apart. You can Intimidate him, if you have the perk, for puzzle help, or ask what would happen if you failed to stop them. If you intimidate him, he will tell you the solution outright: Whale, Eagle and Snake are symbols above the doors. You can them ask him about what would happen. He says his spirit would "ravage the Rift," doing their bidding.

You can now use the doors, even though they have spells on them like ice or fire. The correct doors do not hurt you.

In the first room (ice), the whale is the western door. In the second room (fire), the eagle is the eastern door, directly across from you. In the final room (poison), the serpent is the northern door. 

Saving Valdur
In the final room, defeat all the Worm Cultists to stop the ritual. Then, exit through the door and talk to Valdur, who is free once more. With his shackles destroyed, it will be impossible for the cult to bind him. He vows to help you stop the Worm Cultists and gives you a reward, his shield and some gold. 
  

Quest Stages