Temple of Ikov

Start out by talking to Lucien outside the Flying Horse (Ardougne bar) he will tell you about the Staff of Amarydyl, and he will give you a pendant, he will also tell you that you need an ice weapon to kill a fire monster.

Go now to the tunnels north of Ardougne (large white square with pillars) and go through the room of fear (animal skull in middle of it) and down the stairs. Make sure you have your candle here. Cut the webs to get the boots of lightness. Now go past the room of fear to the room with the skeletons, and put on the boots of lightness to cross the bridge. Now grab the lever piece.

now go past the skellys and disarm the lever and pull it. Now go back to the beginning of the tunnels and into the room with the ice spiders. now get some ice arrows (i needed 50 at lvl 35 ranged) this is easy, but time consuming because every time you grab an arrow you are teleported back to the beginning of the tunnel.

Now get your limpwurt roots, the lever piece, and some food and go down past the lever you disarmed. Place the lever piece in the bracket near the top of the wall, and kill the fire monster with your arrows. Now you will meet a witch. Use the teleport option to get across the river. Now go up the tunnel past the strange looking wall and grab the key. Now go into the room with all the guardians. TAKE OFF YOUR PENDANT OF LUCIEN!

Talk to one of them and eventually select the "I need a bath" option. They will tell you Lucien is evil and then give you a pendant that lets you kill him.

Go to Lucien's house north-west of Varrock and kill Lucien (he's easy, he's less than lvl 20) to complete the quest, and get your reward.