Instructions
Talk to Duncan after having the dream where you learned the new keyword. Use the keyword, "How to reach Tir Na Nog," on him and he will direct you to a man called Tarlach.
Head to Sidhe Sneachta and speak to Tarlach. Select the same keyword. Unfortunately, Tarlach is no help.
Equip the title "Ogre Slayer," "Bear Slayer" or "Golem Slayer" and go to speak to Kristell in Dunbarton. Use the "How to reach Tir Na Nog" keyword and she will give you a new quest called "Duncan's Call." You need one of the slayer titles equipped so you appear strong enough to take on the quest.
Head to Tir chonaill to talk to Chief Duncan and then go to Math dungeon with the second half of Mores' torque. Return and you will have the keyword "Cichol."
Use the new keyword on Duncan and he will spill everything. You need to save the goddess in Tir Na Nog.
Speak to Tarlach with the "Cichol" keyword and he will send you to Kristell. Use the "How to reach Tir Na Nog" keyword on Krystell and remember you need the "Ogre Slayer," "Bear Slayer" or "Golem Slayer" title equipped. You will be assigned "Kristell's Quest."
Kill a black dire wolf in Dugald Aisle and then kill a werewolf in the Fiodh Dungeon in Dark Eden. Eliminate an ogre in the Gairech Hill fields.
Talk to Kristell to get a Red Wing of Goddess and then wait until a real-life Saturday before you head off to Tir Na Nog.
Place the black pass on the altar and then defeat the enemies in Barri Dungeon.
Go to the treasure room and open the hidden door behind the goddess statue. You are now in Tir Na Nog.