No, we're not talking about the original Japanese Resident Evil game title - it's Old School RuneScape Quest called Biohazard. It's quite a long and difficult mission, so a guide is useful. You wouldn't be here if you're looking for him, so keep reading!
Before you cross the Border
Before you begin the mission, you must complete the Plague City mission. If you want to complete this task right away so that you can start over with it, you should check out other guides.
You will also need a chapel and a blouse, as well as a gas mask. If you want to get one for free, you can buy it at the home of Edmond and Alrena in eastern Ardougne.
Although not entirely demanding, it is better to teleport and have some energy or endurance. They are worth the OSRS gold, which should be spent for convenience.
To start the search, you need to talk to Elena in eastern Ardougne. She'll tell you to talk to her father's friend, Jericho.
It communicates through pigeons with West Ardougne, so it makes sense that it asks you to get a pigeon cage and bird food. The first one is behind the house and the second in the closet.
The guide will not confuse you, here is a small context: the capital Ardougne is divided into two parts: East and West. As the name of the search suggests, the latter is influenced by the plague. If you have already completed the Plague City mission, you already know it.
If you come back, talk to Omart. You will find him at Ceril Carnillean's house, southwest of the castle. He will tell you that it is difficult to enter the city because the guards are too close to the wall. You need distraction for this, so you have to go to the small watchtower by the wall, which is directly north.
There, go to the point where the two fences meet. Bird food should be placed on both fences. Then click a frame. Omart then calls on Kilron, his assistant, to hand him a rope ladder. Climb it and you'll reach West Ardougne.
Going to the plague-stricken half of the capital, go to the mourner's headquarters. However, you are not allowed to enter because they are eating stew. To enter, you must distract them. How? Dropping a rotten apple into a goulash cooked in the yard. To get fruit, you need to squeeze through a hole in the fence and put an apple on the ground next to it.
Mourners will tell you that many of them have been affected by food poisoning and need a doctor. This is your signal to go to Sister Sarah's house, in a building southwest of West Ardougne Church. You will find a medical dress there. Wear it and you will be able to enter the mourner's headquarters. Inside, kill one of the mourners, find Elena's distillery in one of the chests, and then go to Kilron, southeast of Ardougne to return to East Ardougne.
Discovering the truth
In the next part of the quest, go to Rimmington. It's best to teleport to Falador, Draynor Village or cabbage. In Rimmington, head to the southwest corner where you will find a pharmacy. It gives you the chemicals you need to search. You give them to three grocery stores, namely Chancy the Gambler, Da Vinci the Artist and Hops the Drinker.
Then put on a priest's outfit and head to the fenced area southeast of Varrock. You can buy one at Thessalia's beautiful clothes shop for 10 coins or from the owner of a fashionable outfit shop in the north of Guidor for 12 coins. The guard grabs the bottle, but not the plague sample. Take the contagious monster to the Dancing Donkey Inn and talk to the three you gave bottles.
Equipped with the priest's attire, go to Guidor's house, which is located southeast of the fenced area. Give Guidor the vials and sample and tell him that Elena needs a sample. After confirming that the plague is a hoax, return to Elena in Ardougne and visit King Lathias in the eastern castle of Ardougne. Then he will tell you everything about the whole plot.
Performing such tasks Biohazard is quite timely. So what are you waiting for? Choose a mission now and find out what the epidemic in Gielinor looks like!