Old School RuneScape uses the British convention for floor numbering: Ground floor, first floor, etc.
Prince Brand suggests that the player gets Queen Sigrid and King Vargas to marry.
- Travel to Miscellania (fairy ring: CIP), and speak to Advisor Ghrim in the castle to start the quest.
- Speak to Prince Brand or Princess Astrid in one of the rooms next door and a cutscene should follow. Prince Brand and Princess Astrid suggest that you have to marry the King to Queen Sigrid.
- King Vargas says that items have been going missing - you need to talk to various island workers.
- Speak to either Gunnhild by the herbs, Leif by the trees, Frodi on the dock, or Magnus by the mines (they will all say the same thing, you only need to talk to one of them). Apparently, Etceteria came to ask for tithes, the workers refused, and the next day items were stolen.
- Talk to the King again, he tells you to talk to Queen Sigrid.
- Speak to Queen Sigrid in Etceteria. She tells you to talk to her citizens about things gone missing and other stuff, once again criticising the king whenever she gets the chance.
- Speak to Matilda in the marketplace inside the castle walls, and she will tell you the same story as the workers in Miscellania.
- Speak to Queen Sigrid, and update her on the known information. Soldiers have been mentioned in both stories, and she has no army.
- Be sure to have the things you will need for the fight at this point. Remember to take antipoison potions and prayer potions as needed. It is recommended to leave about 10 inventory spaces open for items you're going to use later on during the quest.
- Speak to King Vargas about finding out that the Miscellanians don't have an army either, and he says he could make one, and this is arousing suspicion, so you ask what else you can do to further the investigation.
- Speak to Advisor Ghrim, and he will tell you to talk to people to find out if they had seen any suspicious characters.
- Speak to the Sailor at the docks of Miscellania, and he will mention a group of children who said they had gone to go visit their family in the dungeon.
- Speak to King Vargas to get access to the dungeon. He gives you a scroll with his signature.
- Take the scroll with you and enter the dungeon (in Miscellania Castle, ground floor[?], look for the dungeon mark on the minimap), and you will arrive in a small underground town. Find and speak to a dwarf called Donal, who is at the pub.
The lift is operational again.
- Speak with Donal, who is located in the underground pub. He'll give you a mining prop.
- Head up north, and you will see two dwarf miners. Pick up a pickaxe from the rock if you need one.
- Use the mining prop on the crevice.
- Squeeze through the crevice.
Now, you need to repair the lift using items found in the boxes in the chamber:
- First, take an engine and three beams, three pulley beams, and two ropes from the crates.
- Before you start assembling the whole structure, add five chunks of coal to the engine. If you did not bring coal with you, the chamber has four coal rocks as well as a pickaxe near the dwarves if you forgot one.
- Use a pulley beam on the broken scaffold on the east side of the room to attach it.
- Use a beam on a pulley beam to make a long pulley beam, and then use it with another beam to get a longer pulley beam, which you must attach to the scaffold.
- Use the final pulley beam on the scaffold.
- Use the rope on the scaffold to wind it through the pulleys.
- Use the third beam on the platform to repair it.
- Place the engine on the engine platform.
The lift should be operational now, while making sure you have another rope, click the 'use-lift' on the platform to head closer to the mysteries of the island. (If this option doesn't appear, make sure you have added 5 coal to the engine. You can do it when placed on the engine platform.)
- Take the plank and enter the tunnel. Travel east and use a rope with the overhanging rock to get across the water.
- You will come across the remains of a fire, search it to get the first part of a burnt diary. Read the diary, and save it for later.
- Use the plank to cross the slippery rocks - otherwise, you may be hit for 8 damage. The plank is not left behind and may be reused.
- As you proceed further into the caves, you will come across two more fire remains, search them to get the second and third part of the diary. After the third fire remain, there will be some vents in the ground. Do not walk across or stand on them as they repeatedly damage you depending on your Hitpoints level.
- After the vents, there will be another fire remain, search it for the fourth part of the diary. Going further down into the caves, there will be some rocks lying on the cliffs above your path, do not stand or walk under those rocks as they will fall down on you and deal some damage depending on your Hitpoints level.
- After progressing through the area with the rocks, you will come across yet another fire remain. Search it to find the fifth and final page for the diary. Once you have completed the diary, you must read it before being able to enter a crevice at the end of the passage.
- Enter through the crevice, and you should see a cutscene involving some lost kids. The kids had apparently not been able to pass the trials to become a Fremennik, so they were going to start a war here and then stop it, and be seen as heroes. They are to blame for everything. When it's done, talk to them; they will let you know that you need to fight a sea snake.
- Travel out through the next exit, and roam the passages where there are lots of sea snakes and snake spawns until you reach another crevice; squeeze through and kill the Giant Sea Snake (level 149).
A player fighting the Giant Sea Snake.
Protect from Melee works fine (Protect from Missiles if ranging or maging), but its poison damage hits 9 so an antipoison is strongly recommended. Pick up the box that it drops. If you forget to collect the box before leaving, speak to the guard outside the dungeon on Etceteria. After the fight, it is also recommended to immediately drink your antipoison because the damage of the poison is very slow, yet heavy.
- Return through the crevice. A guard will notice you and help you up, and you will surface near Sigrid's castle.
- Go to Queen Sigrid and talk to her, she'll be impressed with you, and she'll give you 20,000 coins as a reward and a letter to take to King Vargas (reading it will not affect the quest).
- Talk to King Vargas to give him the letter for your reward. Quest complete!
- If the player asks the guard in Miscellania if they can go down the dungeon before they gets permission to go down there, the guard will say "You're the regent? Well I didn't vote for you!" This is a reference to Monty Python and the Holy Grail.
- The examine text of the empty box is "It says 'To the dungeons' on the side", a reference to the Metal Gear Solid game series since the protagonist of Metal Gear Solid, Solid Snake, can use cardboard boxes with "To the _____" printed on the side to sneak around in (with _____ being one of three in-game locations depending on which cardboard box is currently being worn).
- The examine text near the lumberjack is "He's a lumberjack and he's okay.", another reference to Monty Python.
- If the player switches their gender between Throne of Miscellania and this quest, various humorous lines such as "Weren't you a man when we last met?" are said throughout the quest.
- "Those Meddling Kids" may be a reference to Scooby-Doo, in which the antagonist would almost always say "I would've gotten away with it too, if it weren't for those meddling kids."
- Another Scooby-Doo reference happens later on in the quest when one of the children say "And we would have gotten away with it too, if it wasn't for that giant snake."
- Armod's full name is shown to be "Armod Brundtson" within Armod's Diary. This is a clear reference to him being the son of Brundt, the Chieftain of Rellekka.
- A Dwarf multicannon can be setup in the boss room to help lower levels defeat the Giant Sea Snake.