Head south from the Aman'lu teleporter, turning east just past the North Gate Sign. Head up the rise and enter the empty house. There's a sparkly Intriguing Stone on the table in the northeast corner inside. Pick it up to initiate the quest and trigger a cut scene of the Assassin attacking an armored character, supposed to represent your active character. Head outside and speak to Danadel for some information about the assassins and what my be done about this one.

You need access to Kalrathia, which occurs in Act III, Chapter I (Restore Kalrathia's Water), in order to continue this quest. When ready teleport to Kalrathia and head east down the stairs, then turn south and go through the door to the west. Turn south and note the star on your small compass map. Head forward and speak with Enchantress Valeria. Tell her that Danadel sent your party from Aman'lu to see her. She will tell you some more about the Assassins and ask that your party bring her a special Dwarven Mythril Ring from the Mines of Kaderak.

You need access to The Upper Mines of Kaderak, which occurs in Act III, Chapter IV (The Mines of Kaderak), in order to continue this quest. Return to the Kalrathia teleporter and travel to the Southern Desert of Kaderak. Head east up the hills, then north up the next hill and continue north to the Kaderak Mines elevator entrance. Move around to the east side and enter so our party can throw the switch to bring th elevator up. Get on and throw the switch again to descend into the Upper Kaderak Mines. Head south down the long passageway and continue south until reaching stairs. Head up two stairways, then turn east and enter the doorway. Head to the rear of the room and activate the switch on the floor to open the secret room beyond. Enter the room and get some gold and the Dwarven Mytrhil Ring from the clearly visible large chest. Teleport back to Kalrathia.

Head east down the stairs, then turn south and go through the door to the west. Turn south and head forward and speak with Enchantress Valeria. She'll enchant the ring and return it to your party. She notes that your character wearing the ring will be able to see the Assasin as long as the ring is worn. Equip the ring on any character, then head east out of the building and enter the travern to the south. Turn and go through the double doorways to the east. Head up the stairway and enter the room through the northern doorway. Speak with Merchant Kendril to cause the Assassin to appear. Engage him in battle as you would with any other enemy and kill him to collect Luun's Deathblade longsword Citaa and shortsword Giethaa as spoils of the battle. Speak to Merchant Kendril again to receive a small reward and very begrudging thanks for saving his life. This completes this quest although your party can return and give the good news to Danadel if you wish.