This guide is suitable for current RuneScape and Old School.
Start the quest by talking to Eluned in Isafdar (part of the Roving Elves quest). Before starting the quest, it is recommended to get a barrel of coal-tar just like you got it in Regicide. If she isn't there, simply switch a world or wait a minute or two. Once you do so, you'll be teleported to a new elves village, by the name of Lletya. Talk to Arianwyn, who will reveal to you that the mourners in west Ardougne are actually elves. He will ask you to discover what the mourners are planning, and stop their evil plan. You will be given a teleport crystal, which will teleport you to Lletya at anytime. It can be recharged by Eluned after its charges have been emptied.
Getting a Mourner Outfit
Go to Arandar, with 7 free inventory spaces. Kill a level 11 Mourner. Note: the mourner will throw a potion at you, that will drain ALL your combat stats to 20 but summoning (including Constitution). It is advised to bring a super restore potion. It is also recommended to use a high hitting weapon's special attack, since if you one-hit the mourner your stats will not be drained. Dragon claws are a good weapon. Pick up the mourner's shirt, legs, boots, gas mask, cloak, boots and letter. You will be able to wear them, except the shirt that is stained with blood and the trousers, that got tore.
You will need to remove the blood stains from the shirt by talking to Tegid in Taverly. He will not let you use his soap, so you will need to steal one from his basket. With a bucket of water, use the soap on the shirt to clean it and be able to wear it.
To fix the trousers, speak to Oronwen in Lletya. She is located in the north-western part of Lletya. With a bearfur and two silks, she will repair your trousers for no cost. After a minute, you will receive your trousers back. Also, buy yellow, red, blue and green dyes from her store. It's recommended to buy 2 of each, incase you fail using them in the future, which will most likely happen once.
Wear nothing but your mourner's suit, and head to the mourners' HQ in west Ardougne (north-east corner). Go down the trapdoor in the first floor, and speak to the head mourner who is in the south-eastern room. Show him your letter, and he will tell you that the mourners' aim is to keep people believing in the plague. He'll tell you that the mourners have dyed Farmer Brumty's sheep, but the colour is fading. Unfortunately, the gnome will not tell them how to fix the gnomic device which is used to dye the ship. You will be given a tarnished key and a broken device.
Use the tarnished key to get in the room with the tortured gnome, and talk to him. You will find out that he loves tarnished crunchies and hates being tickled in the feet. Use your feather to tickle him, and then bribe him with crunchies. He will finally surrender, and will ask you to get a magic log and soft leather, so he can fix the device.
With the dyes in your inventory, head to the swamp south east of Castle Wars and use your dyes on the Ogre Bellows. Then, use the bellows on the toads to get coloured toads (it is recommended to get more than one of each toad).
Head to Ardougne, and locate all four of the sheep groups from Sheep Herder and dye them. Do so by pressing the "Aim and Fire" option in the combat options tab, and using the arrows and "Fire!" button to shoot the sheep.
Return to the head mourner, who will tell you someone poisoned their stew a long time ago (it was you, during the Biohazard quest.) He will tell you that he wants some citizens to get a version of the poison. You need to make the poison and poison two of the three food sources in West Ardougne. Take a rotten apple north west from the mourners' HQ, and talk to Elena. Her house is located north east of the pub in Ardougne. After a long conversation, you will give her the rotten apple and in return you will receive a sieve.
Poisoning the Grain
Go to the fenced-in apple orchard just south of the Gnome Stronghold and take a barrel. Use your the barrel on the pile of rotten apples, and then use the apples barrel on the apple collector. If you don't already have one, You will need to teleport to Lletya using an Elf Crystal. Once you have arrived, you will need to head west, through the dense forest, go west over the trip-wire and finally head south over the pile of leaves to get to the Poison Waste area. Once you are there, you need to use barrel with the tar to retrieve a barrel of Coal-Tar.
Next, you will need to travel to the Chemist's house in Rimmington with the two barrels (Coal-Tar and Apples) and 20 coal. Use the barrel of coal-tar on the Fractionalizing still. Use the same method you used during the Regicide quest to get a barrel of naphtha. When done, use it on the apples barrel, and use your sieve on it. Finally, use it on a range. There is one in east Rimmington.
You will get two toxic powder heaps. Use these on two of the three grain stores in West Ardougne. One can be found on the second floor of the church, and another can be found outside the general store, south-western corner of West Ardougne. Go back to the Head Mourner (remember to wear nothing but your mourner's gear) and talk to him to finish the quest.
Congratulations! Quest Complete!
Guide Made by: Dan
Corrections submitted by: Deathslayer, Illustrial, Dan, Dark, Wise Choice, Power of Five, CallMeMatt, Umbra