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Old School RuneScape Wiki
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It briefly summarises the steps needed to complete the quest.
Old School RuneScape uses the British convention for floor numbering: Ground floor, first floor, etc.

Biohazard continues the storyline after the Link to Plague City Plague City quest. The plot deepens as Chat head image of Elena, File:Elena chathead.png Elena finally gets a chance to process her Item image of %7B%7B%3Aplague+sample%7D%7D, File:plague sample.png plague samples. Buried under these samples lies a well-hidden secret.


Start point Talk to Elena in her house in East Ardougne. She lives right across the road from where you started Plague City. Talk to Elena in her house in East Ardougne. She lives right across the road from where you started Plague City.
Official difficulty Novice
Description This is the second part of an ongoing adventure. Help Elena discover the truth about the infamous Ardougne plague.

Smuggle test samples across Ardougne to Elena's old mentor.

Length Medium


Items required


Enemies to defeat Mourner (level 13)



Items required: None.

Elena's location.

Jerico's house with pigeon cages and bird food.

To begin, talk to Chat head image of Elena, File:Elena chathead.png Elena in Link to East Ardougne East Ardougne, directly west of the shortcut log. She suggests talking to her father's friend, Chat head image of Jerico, File:Jerico chathead.png Jerico, who keeps communication with Link to West Ardougne West Ardougne via his pigeons.

Sneaking back

Items required: Pigeon cage, bird feed

Speak to Chat head image of Jerico, File:Jerico chathead.png Jerico, who lives in a house just south of the northern bank in Link to Ardougne Ardougne and just north of the Link to chapel chapel.

Grab a bird cage from behind Jerico's house and feed from the cupboard inside his house.

Omart's location.

Creating a distraction.

Speak to Chat head image of Omart, File:Omart chathead.png Omart, who can be found west of Chat head image of Ceril Carnillean, File:Ceril Carnillean chathead.png Ceril Carnillean's house in Link to East Ardougne East Ardougne, just southwest of the Link to Ardougne Castle castle. When you talk to him, he says that although he can move you over the wall, it is too risky as the watchtower guards are too close to the wall. The guards need to be distracted so that you can find an opportunity to enter the city.

Head to the small watchtower along the wall, directly north of Chat head image of Omart, File:Omart chathead.png Omart. Stand in the corner where the two spiked fences meet, use the Item image of %7B%7B%3Abird+feed%7D%7D, File:bird feed.png bird feed on the watchtower fence, then click the cage in your inventory.

Go back and talk to Chat head image of Omart, File:Omart chathead.png Omart, who will call out to his assistant, Chat head image of Kilron, File:Kilron chathead.png Kilron, to throw over the rope ladder. Climb over the ladder into Link to West Ardougne West Ardougne.

Infiltrating the Mourner HQ

Mourner HQ is due northeast of West Ardougne.

Head to the Link to Mourner Headquarters Mourners' headquarters located in the northeastern corner of the city. Try to enter, but you will not be allowed in by the Chat head image of mourner, File:mourner chathead.png mourners. Go around the headquarters to the northern part, where you can see a cauldron being cooked in the backyard. Pick up the Item image of %7B%7B%3Arotten+apple%7D%7D, File:rotten apple.png rotten apple laying on the ground just to the west, and squeeze through a gap in the fence into the backyard.

Right click on the rotten apple and use it on the stew that is brewing in the cauldron, otherwise you will eat it. Squeeze back through the fence and walk around to the front of the building, and attempt to go inside again. One of the mourners will tell you that you're not permitted inside because several mourners are ill with food poisoning and are waiting for a doctor.

Nurse Sarah's house.

Head to Chat head image of nurse Sarah, File:nurse Sarah chathead.png nurse Sarah's house - the large building southwest of the Link to West Ardougne West Ardougne church. Search the cupboard in the northern part of her house to obtain a Item image of %7B%7B%3Adoctors%27+gown%7D%7D, File:doctors' gown.png doctors' gown. Equip the gown, and go back to the headquarters. The professional attire will easily fool the mourners into letting you into their base. For all subsequent visits to the headquarters during the quest, the gown must be worn at all times.

Go upstairs and kill a mourner. A Item image of %7B%7B%3AKey+%28Biohazard%29%7D%7D, File:Key (Biohazard).png key will automatically be placed in the player's inventory. Use the key on the gate to get inside the caged room. Search the crates to find Chat head image of Elena, File:Elena chathead.png Elena's Item image of %7B%7B%3Adistillator%7D%7D, File:distillator.png distillator.

Exit the headquarters, and head back to Chat head image of Kilron, File:Kilron chathead.png Kilron at the southeastern corner of Link to West Ardougne West Ardougne. He will help the player get back over into Link to East Ardougne East Ardougne. Alternatively, players can head through the sewers as they are no longer blocked. Go to Elena and give her the distillator.

Getting the touch paper

Items required: Falador teleport or amulet of glory (optional), brown apron (optional) or House teleport if your house is located in Rimmington

The chemist's location.

Elena gives you 4 samples, all of which are fragile and will break upon teleporting. It is advisable to use the drop trick to get at least 2 sets, in case any of them break. Bank the 4 items Elena gives you (there is a bank east of her house, beware that one of the samples resembles an empty vial, however it is not) then teleport to Link to Falador Falador or Link to Draynor Village Draynor Village, or the Link to Explorer's ring cabbage patch. Teleporting or accepting random events with the samples causes them to break and you will need to talk to Elena again to get more. Travelling in a ship will not damage the samples. Withdraw the samples from the bank and go to the Chat head image of Chemist, File:Chemist chathead.png Chemist in the southwestern corner of Rimmington.

While speaking to the Chemist, WARNING: AVOID ALL CHAT OPTIONS THAT STATE YOU HAVE A PLAGUE SAMPLE! He'll destroy it and you have to return to Elena to get a new sample.

He will then give you the touch paper needed to continue the quest.


Items required: Liquid honey, etheneasulphuric broline, and the plague sample.

Chancy, Da Vinci, and Hops are located right outside the chemist's house crowding around a fire. Talk to each of them to give them their respective vials. Make sure to give each bottle to the right person, or you will not receive them when you get to Link to Varrock Varrock. If this happens, you will need to go back to Elena for more chemicals, and go back to Rimmington again.

Give Chancy the Item image of %7B%7B%3Aliquid+honey%7D%7D, File:liquid honey.png liquid honey, Da Vinci the Item image of %7B%7B%3Aethenea%7D%7D, File:ethenea.png ethenea, and Hops the Item image of %7B%7B%3Asulphuric+broline%7D%7D, File:sulphuric broline.png sulphuric broline. Once you have given the vials, they will tell you to meet at the Link to Dancing Donkey Inn Dancing Donkey Inn in Varrock.

Helper Sample Vial Reason
Chancy Liquid honey.pngLiquid honey Owing to its low value, Chancy cannot wager the liquid honey in a gamble.
Da Vinci Ethenea.pngEthenea Da Vinci cannot use the ethenea to create a "work of art".
Hops Sulphuric broline.pngSulphuric broline Hops will not drink it because of its poisonous nature.

So far, so good

Items required: 10 Coins or a priest gown top and bottom, the plague sample and touch paper.

Deposit the plague sample in the bank (there is a deposit box on the northern parts of the docks of Port Sarim, by the Chat head image of Monk of Entrana, File:Monk of Entrana chathead.png Monks of Entrana), then teleport to Varrock. Equip a priest gown set (you can buy one from Link to Thessalia's Fine Clothes Thessalia's Fine Clothes or Chat head image of Fancy-dress shop owner, File:Fancy-dress shop owner chathead.png Fancy dress shop owner to the north of Guidor), withdraw the plague sample and touch paper from Varrock east bank and proceed to the fenced area to the southeast.

Head to the fenced-in enclosure in southeastern Varrock. The guard will search you when you try and pass through the gate. The guard will confiscate the vials if you try and pass with them but the plague sample is safe to bring through. Go to the Link to Dancing Donkey Inn Dancing Donkey Inn with the plague sample and talk to Hops, Da Vinci, and Chancy to get the vials back. Having a full inventory will require you to obtain a new set from Elena. Do not pass back through the gate at this point or your vials will be confiscated on return! (If you have forgotten the touch paper or plague sample, drop the vials at the gate, exit, run to Varrock east bank for the items, and quickly run back to pick up the vials)

If you do not bring the plague sample or papers with you, you can go to Varrock east bank and retrieve them, drop the vials outside, and telegrab them into the gated area.


Items required: The plague sample, touch paper, a priest gown.

Equip your Link to priest gown priest gown and head to Chat head image of Guidor, File:Guidor chathead.png Guidor's house in the southeastern corner of the gated area. Talk to Guidor to give him the vials and sample, and tell him that Chat head image of Elena, File:Elena chathead.png Elena has sent a sample that needs to be processed. After analysing it, he will come to a surprising conclusion. He tells you that the plague is just a lie.

Return to Ardougne

Return to Link to Ardougne Ardougne, and talk to Elena. When you tell her that Guidor found nothing in his results, she suggests that the plague must be a hoax and that you should speak to the person on top of this - Chat head image of King Lathas, File:King Lathas chathead.png King Lathas of Link to East Ardougne East Ardougne. King Lathas is located just south of Elena's house, in his throne-room on the 1st floor[?] of the East Link to Ardougne Castle Ardougne Castle.

When told that the plague is in fact a hoax, the King replies that he did it for the best of his people, and that it protects them from a "far greater danger". He then tells the player about the journey of Link to King Tyras King Tyras - the king of Link to West Ardougne West Ardougne and King Lathas's brother - towards the west and that he has been corrupted by a dark lord after drinking from the Chalice of Eternity. Hence, the wall has been erected between the cities to protect Link to East Ardougne East Ardougne and in turn, all of RuneScape.

Congratulations! Quest complete!


Biohazard reward scroll.png


Required for completing

Completion of Biohazard is required for the following: