0:00 -- Stroud
Here Lies the Abyss is a main storyline quest that is available once the Inquisition has moved to Skyhold. To start it, you first meet with Hawke to learn that he has a Grey Warden contact. This contact is in a cave at Crestwood. The contact reveals that Corypheus is somehow producing a Calling that has pushed the Grey Wardens to extreme tactics. You're invited to witness their extreme measures at a landmark in the Western Approach.
7:18 -- Intro to Erimond
At the ritual site, you discover that a magister named Erimond has tricked the Grey Warden mages into binding themselves to Corypheus. After scaring him off, the Inquisition is forced to face the reality of organizing an assault against the Grey Wardens and Adamant Fortress.
17:50 -- Siege of Adamant Fortress
The assault on Adamant is started through the War Table. The Inquisitor is tasked with tracking down Warden Commander Clarel and stopping a large-scale demon summoning.
21:34, when you reach the Main Bailey, you will discover some Warden Warriors who are battling demons and Warden Mages. After defeating the demons and mages, if you request that the surviving Wardens fall back to safety, you'll be more persuasive once you reach Clarel.
24:17, when you reach the Battlements, you have the opportunity to gain 200 Influence and a good chunk of XP by securing areas for the Inquistion soldiers. Avoid going downstairs until you've secured all 3 areas.
31:57 -- Clarel
Erimond will slip up and summon the dragon of Corypheus. This turns Clarel against him. After a battle against a Pride Demon, you have to pursue Erimond and Clarel.
39:39 -- Clarel's Sacrifice
41:34 -- Into the Fade
In the Fade, the Inquisitor has to reclaim his memories and escape from Nightmare, a powerful Fear demon.
-----------------Fears of the Dreamers-------------------------
This side quest involves finding objects to inspire or calm some entities that are trapped in Nightmare's domain. Each dreamer will reward you with a permanent attribute increase, and if you help them all, you get the Essence of Perfection crafting material.
45:00, first dreamer, south of where you enter the Fade.
1:00:42, second, down some stairs after you hear Nightmare speak for the first time.
1:11:26, third, hug the left-hand wall after the Inquisitor gains the memories from when he last visited the Fade. You'll need to backtrack a bit to deliver this dreamer's object.
1:15:47, fourth, find his object at the east end of the beach; (take the right path from the 2nd major fork in the road to reach the beach).
1:19:13, fifth, take the left path of the 2nd major fork.
1:23:22, right before you face Nightmare, the spirits will gather together around your final reward.
The mirrors also grant permanent attribute increases.
45:44, follow the canyon that is North-East of where you enter the Fade.
1:01:50, hard to miss, it's found right before the first major fork in your path.
1:03:33, take the left path of the fork.
1:12:45, after the Inquisitor gains the memories from when he last visited the Fade, this mirror will be near a group of enemies.
1:16:58, take the right path of the next fork; this mirror is at the east end of the beach.
46:49 -- The Divine
Justinia will guide the party through Nightmare's realm. She first instructs the Inqusitor to regain his memories from when the Temple of Sacred Ashes exploded.
1:06:12, Justinia now has you recover your memories from when you first entered the Fade.
1:19:45 -- Broken Window
Brief sidequest. Light the flames in the correct order. (Numbered left-to-right: 4, 1, 3,5, 2).
1:23:59 -- Boss Battle -- Aspect of Nightmare
The main issue in this boss fight is that Nightmare and spiderlings can inflict large amounts of damage with each attack, so try to keep the party safe with high Barriers and Guard. Nightmare is vulnerable to Spirit and Lightning, so once his Barrier falls, it can be quite easy to damage him.
DO NOT IGNORE the enemies that join the battle. They do not die if Nightmare is defeated, and sometimes, Nightmare will leave, and he will not rejoin the battle until you have killed his help. Also, the Spiders can deal a good bit of damage with their ranged attack, so you really want them dead as soon as possible.
1:27:49 -- Escape from the Fade
1:33:40 -- Solas is Pissed
1:34:38 -- Comfort from Mother Giselle
1:37:07 -- Dagna is Excited