In this quest you get a guide, a spectre by the name of Kolos, talk to him and then enter level 17. Explore the level a little and you will run into Kolos standing before a door, he will tell you there is a powerful spell book in this room, and you must kill the occupants to test your strength. The book is just a normal book of stone; it is not needed for the quest.

Explore further and you will eventually come across another room. Kolos tells you this room is inhabited by a druid who will no doubt try to trick you, and warns you not to enter. Enter the room anyway, and you will find 6 book stands, a chance to find a few books to increase your spell knowledge. Then talk to Atenus 3 times, which causes him to invoke a fire golem and attack you. Kill them both and Atenus will drop the Vial of Spirits, which you will need later in this quest.

Now down to level 19 I believe it is, and you will find 2 large rooms. One with 2 magic elixers guarded by some Gorgons, again these aren't needed for the quest, but elixers are always nice to have. The other room will contain a crystal, again guarded by Gorgons. However, when you go to take the crystal, your faithful guide Kolos appears to steal it away from you. It seems he is one of Draaks minions who was just using you to gain access to the crystal.

That's not the end though, go down to level 20 and you will find 3 coffins in a room similar to the 2 on the previous level, one of them being Kolos' coffin. Use the Vial of Spirits on the coffin below Kolos' ghost, and the 3 spectres will attack you. Kill them, and once you kill Kolos, he will drop the Crystal of Compassion he stole so deceptively last level.