Start by talking to King Lathas, upstairs in East Ardougne's castle. He'll tell you his scouts found a path to the Well of Voyage, an ancient portal to west RuneScape, but will explain it's been taken over by a madman named Iban.
He'll tell you to meet Koftik, his main tracker. You will find him at the far west side of West Ardougne. If you don't have the ropes, bow, and arrows, you can buy some from the West Ardougne General Store on the way there.
It is recommended to bring high level food. This dungeon is EXTREMELY dangerous. Be sure to leave a couple inventory spaces open for items you will receive in the pass.
When ready, go to Koftik, located to the very west of West Ardougne. After talking with him, head into the pass. Head west. Using your mini-map, click across the green swamp area.
Talk to Koftik. He will give you a damp cloth. Use it on one of your arrows, then use the unlit fire arrow on the nearby fire. Go to the area north of Koftik and the fire, and click on the guide rope, on the north side of the bridge. The bridge will fall and you will run across.
Head north and grab the plank on the ground, you will need it later. Run south, then follow the path east. You will see some spikes on the ground on either side of a pit. Use your rope on them, and you will attempt to walk across.
If you fail, you will appear below the dungeon. Make your way through, and you will appear back up near the beginning. Repeat previous steps to get past.
After crossing, follow the path, and climb over the rockslide. Climb over the other, and talk to Koftik. He will say some strange things...
You will see a 5x5 grid. The goal is to get the other side. BUT, there's only one correct path, and this varies per person. It is HIGHLY recommended to draw a 5x5 grid on a piece of paper, showing the correct path once you figure it out. You should save this if you plan to ever do Regicide.
You have to guess and check the path. If it's the correct one, you won't fall. If you fall, then try a different grid piece. When you fall, simply climb up the protruding rocks on the wall, and go back to the grid pieces you know work so far.
When you get across, pull the lever on the south side to open the portcullis.
Orbs of Light
Go west, but be careful when the passage narrows: there are traps in the walls! To get past these traps, it is recommended to step on square just before it, stop, then run past to the other side of the trap. Make sure you do this with each trap, each time, to avoid damage.
There are two first on the north side, then three on the south side after that. There are four paths, and four Orbs of Light that you must take.
NOTE: Do NOT pray at the Altar of Zamorak nearby!
The North Path
Use your plank on the Flat Rocks to avoid taking damage from the traps. You will cross over without taking any damage. Repeat for all the traps. Take the Orb of Light, no strings attached this time. Go back near the well, using the plank on the rocks on the way back.
The North-West Path
Run past the blessed spiders and ogres, and take the Orb of Light. Run back to the center.
The Middle Path
Repeat using the plank on the flat rocks to avoid taking damage. Take the orb, and head back, using the plank on the rocks again.
The South-West Path
Run up the end of the path. There won't be any traps on the way. DON'T take the orb just yet! Right click under it, and search the flat rock. Try to disarm the trap. When you disarm it, take the rock and run back to the well.
Destroying the Orbs
Return east, back in the direction of the grid. Remember the traps in the wall! Back near the zombies, use the orbs on the furnace one at a time. After all the orbs are destroyed, return to the well and climb down (remember the traps on the way there!)
After climbing down the well, search the nearby boxes for two Salmon and two Meat pies. This can only be done once!
In the jail area, pick the lock on the south-east east most cage. Dig next to the mud with your spade, and you will push your way through a tunnel. Go west then, and cross the ledge. If you fail, return back to the cell and dig through again.
Note: If you're 50+ Theiving, you can skip this stone bridge part by picklocking the door further past the start of the bridge.
Walk onto the narrow stone bridge that goes over the pit of spikes. You'll have to click to cross the narrower parts. When the path splits, take the south route, then take the north. If you fall, you'll have to go back up and try again. Once you pass, follow the path all the way south, and climb through the obstacle pipe.
Opening the Door
Enter the room, and search the cage the unicorn is in. You'll find a loose railing piece. Run around to the ledge south of the Unicorn. Use the railing piece on the boulder there. It'll crush the unicorn.
Search the smashed cage to find a unicorn horn. Pass through the tunnel on the side of the room.
Follow the path until you come across three Paladins around a fire. Talk to Sir Jerro to receive food and potions. After receiving the items, kill them. They will drop a Paladin's Badge. You must get all three.
After obtaining all three Badges, head west. Use your plank on flat stone to get past safely. You will come up to another well and a door. Use the Unicorn horn and each Paladins' Badge on the well. Once all the items are in, the door will unlock.
Once in the huge chamber, head to the very south side. Along the south wall, more on the east half of the south wall, there will be some stairs going into the wall. Go down the stairs, and into the nearby camp.
From now on, if you ever need food, talk to Kamen. Agree to drink some of his home-brewed ale. You will be hit 50 life points, but a meat pie, stew, and bread. The bread alone will heal the 50 that you were hit.
Now talk to Niloof. He will tell you to seek the witch on the floors above to learn how to Kill Iban. He will also give you some food.
NOTE: If you fail any of the bridges, you will appear down below. Simply head south and climb up the stairs near the dwarf camp and try again.
Go back up the stairs, and head north along the east side of the room. Go onto the first path onto the bridge. Jump across the bridge, and go south to the house. Search the window next to the door.
She will be searching for her cat. Go back north, and take the bridge west. After crossing the next pieces, follow the path north. You will soon see the witch's cat. Pick it up, and return to the house.
Use the Cat on the door, and you'll automatically knock and walk around the corner. She'll take the cat inside, you can now enter because she's busy playing with the cat.
Search the nearby chest inside, and you'll receive two potions, a book, and a doll.
Return to the Dwarves, and talk to Niloof. He will tell you that Iban's four elements are being guarded somewhere in the cave.
Talk to Klank. He will give you a tinderbox and his gauntlets. Go into the larger building and take a bucket from the spawn there. Then, go in the smaller building, and use the bucket on the barrel in the room to get some dwarf brew.
Exit the camp and go to the south-east corner of the cave. You will find Iban's tomb there. Use the Dwarf Brew on the tomb, and use the tinderbox on it. It will light on fire, and you will automatically search and find Iban's ashes. Use it on the Doll of Iban.
Go to the very north-east corner of the lower cave. You will find an area full of spiders. Enter it, and look for the largest spider: Kalrag (level 89).
You may have to kill some other spiders before you can attack Kalrag, as it's single combat only. After it's dead, you will smear its blood onto the doll.
NOTE: All nearby spiders will start attacking you, despite it not being a multi-combat area. If you have low LP, you may die!
Head up the stairs near the Dwarf camp. Take the first path onto the bridge like last time when going towards the Witch's house, except go past the house, west. After the second bridge, go south (you went north last time for the cat).
Kill each demon on the platforms, and take the amulet they drop. You can safe them from the paths and use magic or range. After you have all three amulets, go to the chest north of Doomion. Open it to recieve Iban's Shadow. Use it on the Doll of Iban.
Go to the north side of the upper cavern (if you fall from a bridge, there are stairs to the very north-west of the lower cave, so run to them instead of running south to the dwarf stairs, only to run north again).
Make sure you're wearing Klank's Gauntlets, then search the cages the soulless are in until you find a Iban's Dove. The cage that it is in is different per person, so just keep searching. You'll have to cross different bridges to get to the different cages sometimes.
Use it on the Doll of Iban.
Now that you have a completed doll, you must go kill Iban. He is located in a room in the very center of the large upper cavern.
If you're low agility, it is recommended to use the path with the fewest bridges to jump. The start of this path is in the west side, third path from the north. It is just south of the Soulless cages, and there is a jump at the very beginning. Follow the path east, then south.
Once you see the Disciples of Iban, you must kill them to obtain the Zamorak robes. You must wear nothing but the robes to be able to go into Iban's chamber. Once you're in there, it is HIGHLY recommended to use Protect from Magic if you can.
Use the doll on the well, and try to avoid Iban's attacks. After you throw the Doll into the fire, Iban has finally gone to rest. Amongst his remains, you will find his staff and some runes.
"Suddenly around you rocks crash to the floor as the ground begins to shake... The temple walls begin to collapse in... and you're thrown from the temple platform."
You will appear in another cave. Follow it west to find Koftik. He will have no memory of what happened. Koftik was under Iban's influence, but is now unaffected since Iban is dead.
He'll show you the way out to the beginning of the dungeon. Go talk to King Lathas back in East Ardougne to claim your reward!