There's been a strange disturbance at the Temple of Light, and Arianwyn wants you to help. He also wants to come with, which is a bit of a problem since the Mourners might recognize him. It's up to you to get a disguise for him and create a distraction (with the help of the gnome inventor the Mourners have captured). Once that's done, you can attune a teleport seed to the temple of light and teleport there with your elf companion. While he catches up with Thorgel, you investigate a strange energized pillar. Poking it with your crystal trinket will get a reaction, but it's not strong enough. To actually make something happen, you'll have to poke it with yourself, energized with the same power that's in the trinket. Thorgel will help you up onto the Death Altar, and after that all you need to do is poke the power crystal in the temple and then touch the pillar to be immediately teleported somewhere else.
This 'somewhere else' has another light puzzle for you, although thankfully it's nowhere near as long or complex as the last one. After you solve the puzzle and navigate an Agility maze to hit a target with a massive ballista, a massive stone door will open, revealing a caved-in tunnel. Someone else is there before you, again, but it's not anything you did- he just came from the other end. The guy mentioned in the dead mourner's journal to be searching for the Prifddinas Undercity actually found the place, and a tunnel leading from there to where you are. However, the tunnel was unstable, and the messenger was killed by a cave-in.
Report back to Arianwyn, and he'll put Thorgel and compatriots (who are on your side now to make it safe for them to return to Keldagrim) to the task of clearing out the cave-in and opening the way to eventually restoring Prifddinas, which was reverted to crystal seed form long ago. Congratulations, quest complete!
This quest contains the following tropes:
- Chekhov's Gun: The dead mourner's journal mentions that his cousin was searching for the Prifddinas undercity. This quest reveals that he found it.
