You will be tipped-off to this mission by Lester, standing in his usual spot. He'll force-talk to you when you pass near.
Inside the temple, Y'Berion will cryptically say that he "knows your face," which you will say is impossible, before giving you your first assignment: the Sect Camp requires a specimen of the artifacts that were used in the original barrier creation known as Focus Stones to contact the Sleeper. The location of one such Focus was noted and the novice called Nyras - you might have tried to talk to him before: rude guy on the right path from the entrance - was sent to retrieve it, but he hasn't returned. You are asked to go to the location, as indicated on a nice map he gives you, and find out what happened.
The area is actually RIGHT ABOVE the temple you should be exiting now, but there is no way to directly reach it without leaving the Sect Camp. Follow that path leaving the camp until you come to the forest and a fork in the road. Take the fork right, with the forest to your left and a wall to your right, all the way around, until you pass (or fight) a group of Scavengers. After that group, hang right and you will come to a cliff eventually, where you will see a stone pedestal on the ground and a Sect Camper standing behind it. This "stone pedestal" is the usual and original dais used for the Focus Stones, and the "Sect Camper" behind it is Nyras.
When you approach the pedestal, Nyras will hail you. He says he has the Focus Stone with him but that he received a vision from the Sleeper that is self-glorifying and ... the short of it is that he's not giving the Focus to you and will now attack you on sight until you beat him down or kill him. It doesn't matter whether you just stun him and steal all of his precious things, especially the Focus Stone, or kill him and loot the corpse; no one seems to care either way, which is terribly sad. Nyras, if you don't kill him, goes onto live a very lonely life as a hermit on the cliff, frequently running away from you whenever you approach him, and never picking-up any interesting dialogue. Once, he was so scared of my approach, that he ran right off the cliff and dashed himself from the game on the temple courtyard floor.
Return to the Sect Camp and give the Focus Stone to Y'Berion. Y'Berion will, in turn, ask you to deliver it to Cor Kalom in his alchemy laboratory. Doing so will complete the quest and open-up Kalom's dialogue for the next quest.
An interesting thing to be noted is that Y'Berion and Cor Kalom will accept any of the Focus Stones for the completion of this quest, only that the cliff-side Focus Stone happens to be the easiest to retrieve and is actually just the intended quest solution. There are no triggers except returning to Y'Berion with a Focus Stone in your inventory. Because "all" the Focus Stones are loaded into memory at the start of the game and can be retrieved by a combination of aggro-abuse, transformation scrolls (Meatbug), and Telekinesis scrolls, it might be possible to grabbing all five before even starting chapter two.
Another thing to consider, only hypothetical for now: there is a Focus Stone loaded into the memory of Cor Kalom's always-locked chest in his alchemy laboratory but it is difficult to determine if that Focus is always there or if it is whatever Focus you retrieve for Y'Berion in this mission. Cor Angar will present you with the key in a future quest but, provided the key exists in someone's inventory prior to that quest and the Focus is legitimately something that normally exists in the chest, it might be possible to pickpocket the key, and acquire this "sixth Focus Stone." Finding the key, if it is in somebody's inventory, is the first step.