Bypass Hedge & Terris Thule Flag (Plane of Knowledge)
This quest grants you an alternative means of accessing Plane of Nightmare B. You'll need to speak with Veriok Dreik in Plane of Tranquility and then to Kelletia in Plane of Nightmare. After you do this you'll need to bring Kelletia three items that drop from Plane of Nightmare; the first of which being Heart of the Tyrant which drops from The Tyrant Nighmare near the PoNightmare B entrance.
Once you bring Heart of the Tyrant to Kelletia you'll be asked to bring two more items, Secured Wooden Case (Terror Matriarch Drop) and Silky Cloth (Spiders in PoN). Return both these items to her and then once that's complete return to Veriok Dreik to complete the quest and receive your flags.
Hail, Veriok Dreik
/say I believe
/say what nightmares?
/say what jeweled dagger?
/say I will find her
/say what work?
/say What Nightmares?
/say I can help
Note: In order to complete this quest you'll need to have the Saryrn flag which you obtain from the Plane of Torment. If you haven't obtained the Saryrn flag Veriok Dreik will not even speak with you.