Online:The Star-Gazers

Quick Walkthrough
# Find the Star-Gazer Herald in Mournhold, Wayrest or Elden Root.
#* or read A Dire Warning in Belkarth or near Bangkorai Gate.
# Ask the locals in Belkarth about the Star-Gazers.
# Talk to Hara in the Star-Gazers' Observatory.
# Receive the Star-Gazers' blessing.
# Talk to the Thief.
# Talk to Hara.

Detailed Walkthrough
|thumb|right|The city of Belkarth
A Herald
In Mournhold, Wayrest or Elden Root, you will encounter a Star-Gazer Herald:

:"Doom has come to Craglorn! The stars have vanished from the sky!
:"Will no one listen? Will no one help?"
:;The stars have vanished? What are you talking about?
:''"I'm an initiate in the Order of Star-Gazers. We study the stars and their influence on Tamriel.
:Not long ago, we noticed irregularities in three of the star signs. Shortly thereafter, strange armies overran Craglorn."
:;How can I help?
:"One of our order, Hara, is leading our efforts to stop these attacks. But we're not warriors.
:This cart will take you to Belkarth, in Craglorn, where you can speak to her personally. Please, help us."''
:;Very well. I'll aid you as best I can.

Board the cart next to him, which will take you to Belkarth.

A Dire Warning
If you are already in Belkarth and have not yet started the quest, you will find A Dire Warning pinned to a nearby noticeboard:
:"Traveler, beware! An army of unknown warriors has been attacking convoys in the western wilds, while a massive force of atronachs threatens all who take the eastern road. Do not leave the city without military escort!"
:"The Star-Gazers, a group of scholars devoted to the study of the stars, seek able-bodied warriors from across Tamriel to face these threats. If you would lend your aid, please contact Hara at the hilltop observatory in Belkarth."
You resolve to find Hara and offer your aid.

Ask About Star-Gazers
From the Belkarth Wayshrine, head south along the path. Just off the path, you will find Slonn Clod-Kicker:

:''"I didn't put any stock in the words of those Star-Gazers until I saw my first sand giant. It cut a horse in half. I haven't run so fast since I was stealing meat on the streets of Riften.
:''Now we're all listening a bit more closely."
:I'm looking for the Star-Gazers. (only appears if you do not yet know where they are)
:"Everyone is, these days. Funny how a few months ago, they were just a bunch of star-obsessed loonies. Now, they're the only folks with any idea what's going on.
:''Their observatory is up on top of that big hill there. Can't miss it."''

Find the Star-Gazers
Keep following the path, until you come to a tower - the Star-Gazers' Observatory.

Once inside, find Hara: 

:"Speak quickly. I am very busy and our Order is stretched to the breaking point."
:;I understand you've been having some problems. I'm here to help.
:''"Of course. I'm sorry. You've come to help us, and I'm being rude.
:;I need to know the situation. Tell me what's going on here.
|thumb|right|Undergo the ritual to become one of the Star-Gazers
:''"Then I'll start from the beginning. A short while ago, the three guardian signs—the Warrior, the Mage, and the Thief—vanished from the night sky."
:;What happened?
:"I wish I knew. I've studied the stars my whole life. I've heard them speak—but now they're silent. It's eerie.
:All I know is when the guardians disappeared, three powerful beings started attacking Craglorn. They call themselves the Celestials."
:;The Celestials?
:"I don't know. It's not a name I'd ever heard before.
:Two of the Celestials identify themselves as the Warrior and the Mage. The third, strangely, calls himself the Serpent—after the thirteenth constellation. The Thief is nowhere to be found."
:;What do you need me to do?
:"The Star-Gazers consists of scholars who are no match for the current threat. We need champions to face the Warrior, the Mage, and the Serpent. And, if possible, to find the Thief.
:Join us. Be our strong arm, our sharp sword against the Celestials."''
:;I'll join you.
::"Thank you. We have a lot of work to do. But first, you must become an official member of our order.
::Enter the circle of stars and accept our blessing.
:;Let me think about it.
::"Of course. But don't take too long. The Guardian stars have protected Tamriel for centuries. How long can we last without their favor?"

Becoming a Star-Gazer
Do as Hara bids, and use the ritual circle inscribed on the floor.

The Star-Gazers will begin chanting:

"Stars above, let this new light do your will."

However, after the ritual ends, you find yourself in a room full of bookshelves and the Thief.

:"Forgive me. I did not know any other way to contact you without revealing myself. Even now, the Serpent's followers, the Scaled Court, are searching for me."
:;Who are you?
:"I am the Celestial Thief. I appeared with the other guardians when the Serpent broke free and manifested in Tamriel.
:One by one, the Serpent trapped the others. First the Warrior, then the Mage. He wants to do the same to me."
|thumb|right|The Celestial Thief
:;Are you saying the Serpent is controlling the other guardians?
:"Yes. They attack Craglorn against their will.
:Listen. The Serpent's nature is chaos. He wants to undermine the very nature of reality. He will not stop with Craglorn." 
:;How do we stop him?
:"My power alone is not enough. You must free the other guardians. I will help you as much as I dare, but the Serpent is looking for me. If he ensnares me as he has the others, all is lost."
:;How do I free the Guardians?
:"Hara and the Star-Gazers will help you. Use their knowledge. Look for the presence of the Scaled Court—where they are, the Serpent is surely at work. 
:But you must not tell anyone you saw me. The Serpent's followers are everywhere."
:;Are you really the Thief constellation?
::"In a way. Just as you might look at a picture of the star signs and say "That's the Thief" or "That's the Warrior." Just so, I'm the Thief, or one way of seeing the Thief."
:;Tell me about the Guardians.
::"Of the twelve rightful star signs, it's the Guardians' duty to protect the lesser signs, our charges, against the destructive ways of the Serpent.
::With the Warrior and Mage under the Serpent's control, their charges are vulnerable. So is Tamriel."
:;You know Hara?
::"It would be surprising if I didn't.
::The Star-Gazers are only dimly aware of it, but they carry an ancient legacy as students of the star signs. Their devotion has not gone unnoticed."

Once you are finished talking to the Thief, return to Belkarth via the newly-opened portal beside her.

Return to Belkarth

Once you are back in the Observatory, return to Hara:

:"The stars have accepted you. I just hope it is not too late.
:Volumes of prophecy have been written about the stars, but not even the oracles foresaw these events."
:;Where should I start?
:"Gather allies before you leave the city. You'll need loyal friends to face the armies of the Warrior, the Mage, and the Serpent.
:Return to me each time you learn something new. I will use what you learn to devise a plan to defeat the Celestials."''

Celestial Investigations
Once the quest is complete, you can ask Hara what she knows about the Warrior and the Mage. Each question will point you in the direction of starting one of the following quests:
Asking about the Anka-Ra will mark Bangkorai Gate on your map, which is the starting point for The Warrior's Call. Brown-Tooth will also offer this quest from just outside the Observatory entrance.
Asking where you should start investigating the Warrior will point you to Erold. He can be found in Belkarth's inn, and will offer The Corrupted Stone.
Asking about the summoned atronachs will mark the Proving Grounds Dolmen on your map, which is the starting point for Elemental Army. Engariel will also offer this quest from just inside the Observatory entrance.
Asking about the magical events in the Craglorn foothills will point you to the Crossroads Tavern. Star-Gazer Nudryn will offer the quest The Shattered and the Lost.

Notes
Of the four follow-up quests, only The Warrior's Call and Elemental Army are required to unlock the subsequent storyline quests.
 

Quest Stages