It is highly recommended to do this quest on World 88, as that world is the designated for a part of this quest. It is impossible to do this quest by yourself!
To start, head to the building marked on the map and right-click search the broken table. You will find some herbs. Now, search the shelf on the wall to find the Diary of Herbi Flax. Read (or skim) through it. Pick the vials up off the ground, and head to the building to the northeast and fill the vials up in the sink.
Add tarromin to the vials of water, then add ashes to create Serum 207. Head into the General Store building to the north and use the serum on Razmire. Ask about the shadowy creatures. He'll ask you to kill 5 shades and pick up their remains.
Return to Razmire and use the Serum on him again. He'll take two remains, and suggest you talk to Ulsquire. Razmire will now trade with you as well. Return to the building with the sink and use a dose on Ulsquire. He'll take the remains.
Rebuilding the Temple
Talk to him again and ask what he found out. He will talk about rebuilding the temple to the north. Return to Razmire, and using another serum, trade him. Buy some Olive oil from the General store (and optionally the Flamtaer hammer), and about 5 limestone bricks, 5 timber beams, and 25 swamp paste.
On World 88, head north of Mort'ton to the old temple. More than likely the temple is already built. Help reinforce the temple (or repair if it isn't repaired) until your Sancity is about 35. If the fire altar isn't on fire, light it (uses 10% Sancity) and use the Olive Oil on it to get Sacred oil.
It is also recommended to use one of the Serum 207s on it (uses 20%) to make it Serum 208. Using this on Razmire and Ulsquire makes them permanently unafflicted. Talk to Ulsquire to find out what to do next.
In Pyre Need
Go to any of the various funeral pyres around town. Use the logs on the pyre, then the remains, and light it. A key will appear on the nearby stand. Take the key.
Return to Ulsquire to complete the quest!