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Kingdom Come Deliverance Pestilence side quest guide - How to brew the potion and get the Plague Doctor trophy

With Pribyslavitz conquered and a new enemy lurking in the shadows, Kingdom Come Deliverance takes a new twist as Henry investigates a mysterious disease gripping the hamlet of Merhojed.

This quest is complicated and the stakes are high - take too long, and people will die. Here’s our guide to the Pestilence side quest in Kingdom Come Deliverance, with instructions on how to cure all of the afflicted in Merhojed and bag the Plague Doctor trophy.

If you want the trophy, it’s vital that Henry has learnt how to read. You can do this by completing the Mightier than the Sword side quest, which we also have a guide for. That quest causes many in-game days to pass, so we recommend finishing it before you travel to Merhojed. This way you minimise the chance of villagers dying from their illness.

Pestilence side quest guide:

  • Learn to read in the Mightier than the Sword side quest
  • Travel to Merhojed
  • Speak to Mattias in the stable
  • Talk to Melichar
  • Talk to Bedrishka, dig her husband a grave and bury him
  • Talk to Daniel
  • Talk to Vincent
  • Talk to Old Straw
  • Travel to the Sasau Monastery and talk to Johanka
  • Buy Valerian and two Thistles from Brother Nicodemus before you talk to him about the plague
  • Tell Brother Nicodemus about the plague and tell him that half of the houses and all of the animals have fallen ill. Then say “I know” and “I can read”
  • Read the book of the lectern nearest the door
  • Tell Nicodemus that you “know what ails them”, and say “poisoning from water”
  • Say “I can help” and offer to brew the potion yourself, otherwise villagers will die
  • Buy some charcoal from a blacksmith
  • Brew the healing potion
  • Take the cure to Merhojed and talk to Nicodemus
  • Give cure to all the sick people - Straw, Vincent, Daniel and Bedrishka
  • Talk to Melichar and ask to see the captured bandit
  • Cure, wait for and then interrogate the prisoner
  • Talk the villagers down when they come to attack the bandit
  • Wait a couple of days for the situation to improve and speak to Brother Nicodemus

Starting the quest

This side quest crosses paths and overlaps with the main quest Questions and Answers on multiple occasions. To start it, speak to Mattias in the stable about the raid on Merhojed. Question him about the attack and then about the plague.

He’ll tell you to speak to the local Bailiff, Melichar, for more information.

Melichar is usually wandering around in front of the stable gate.

Upon speaking to him, he’ll refuse to let you speak to the bandit needed for the Questions and Answers main quest and say that his fellow villagers are dying from an unknown plague.

Agree to help cure the sick and Melichar will promise to let you at the prisoner. Besides, you don’t have much choice since the bandit’s sick as well.

Make the rounds

If you’re going to cure the mysterious disease, then you’re going to have to get a look at the symptoms.

Make your way around the houses with white crosses on the doors in the village.

On the western side of the stable is Bedrishka’s house. Her husband has already succumbed to the sickness, so help her to bury him and she’ll give you some information about his symptoms.

In the house south of Bedrishka’s, you’ll meet Daniel, who’s delirious. You can try a speech check and pretend to be his brother if you like, but he’s not going to shed much light on the affliction.

Then on the southeastern side of the village, you’ll come across Vincent and Old Straw’s houses next to each other.

Vincent will ask you to take his last will and testament to the priest in Sasau - starting the Will and Testament side quest. Agree, and he’ll tell you about his symptoms.

Old Straw will be more resistant. Tell him that you’re there to help, and he’ll let you see his wife. She’s in one of the rooms to your left as you walk into the house, so go in and “inspect” her.

Travel to Sasau Monastery

When you’ve taken a look at all the sick, ride southwest to the under-construction monastery just north of Sasau. As you enter over the drawbridge, turn right and on your right will be a makeshift infirmary.

Speak to Johanka here and tell her about the plague. She won’t be able to aid with a cure but will go to Merhojed to help where she can. Johanka also says to speak to Brother Nicodemus at the infirmary.

Seek out Nicodemus, but before you ask him about the plague, trade with him.

Buy one Valerian and two Thistles - you’ll need them for the cure.

Once you’ve got those, speak to Nicodemus and tell him about the plague.

Reporting the plague

The first dialogue choice doesn’t matter, but then you have to say “about half of the houses”, followed by “all of the animals”.

Then say “I know” and that you can read, since you should’ve completed the Mightier than the Sword side quest.

If you can’t read you have to describe the symptoms to him, which are: fever, stomach pains and diarrhea. However, this way Henry won’t be able to save everyone, because you’ll have to wait for Nicodemus to make the potion himself.

If you can read, take a look at the book on the lectern nearest the door. Leaf through the pages, then return to Nicodemus and say “I know what ails them”.

Tell him that you think the illness is caused by “poisoning from water”. Then say that “I can help”. Do not get Nicodemus to brew the potion if you want the Plague Doctor trophy, since you’ll have to wait a day for him and people will die.

How to brew the Merhojed potion

If you bought Valerian and two Thistles from Nicodemus before you told him about the plague, the only other thing you need is charcoal, which you can buy from the blacksmith in Samopesh, just northeast of the Monastery.

If you didn’t get the plants from Nicodemus, you can also buy them from the Apothecary in Rattay.

Either way, head to an Alchemy Station - there’s one conveniently placed next to the infirmary, or behind the apothecary in Rattay.

This step is complicated and can go wrong, so familiarise yourself with the steps first so you don’t get flustered and mess up. It’s a good idea to drink a Saviour Schnapps here just in case.

First, use the Alchemy Station and open your inventory with the d-pad, placing the Valerian, Thistles and charcoal on the bench.

Next, add water to the cauldron. It’s yellow and on the shelf to your top left.

Then add two portions of Thistle to the cauldron. Don’t mash them up in the pestle, just pop them straight in. This makes the mixture turn a funny grass texture.

Now you have to boil the concoction for “two turns”. You turn on heat by pulsing the bellows with the left trigger. Press the button 4-5 times until you see black smokey bubbles in the mixture, this means it’s boiling.

When you see the bubbles, press the right trigger to turn the hourglass. And when the first lot of sand runs out, press the right trigger again to flip it over.
Now that the sand has run out for a second time, add the Valerian from the bottom right shelf.

You now have to boil the potion for one more turn. So press the left trigger until you see the bubbles again. Go slowly, because it’s possible to overboil the mixture. Stop pressing as soon as you see the bubbles.

As the bubbles start, press the right trigger to turn the hourglass again.

After the sand runs out, wait for the flames under the cauldron to stop, then add the charcoal from the bottom right shelf.

Then take a phial from the bottom left and decant the potion.

You should get a message on-screen that says you’ve brewed Aid for Merhojed.

To sum up, the recipe is:

  • Add water to cauldron
  • Add two handfuls of Thistle
  • Boil the mixture for two turns of the hourglass by pressing the left trigger 4 to 5 times.
  • Add the Valerian and boil for another turn
  • Wait for the flames to go out
  • Add the charcoal and pour into phial.

Healing the sick

Once you’re finished brewing, ride back to Merhojed and speak to Brother Nicodemus. Ask him about the situation and tell him that you’ve made a cure. He’ll say that he will administer the cure to Old Straw’s wife if you take it to the other villagers.

Head back to Bedrishka, Vincent and Daniel and give them some potion.

Then speak to Melichar about seeing the prisoner, he’ll agree and open the doors to the barn he’s being kept in.

Administer the cure to the prisoner, then wait as the situation develops.

You then need to talk to the bandit and ask him everything you need to know for the Questions and Answers quest.

When the Merhojed villagers burst in to try and attack the prisoner, talk them down by saying “you don’t want to be a murderer”.

Henry will then take him to Rattay jail.

To get the Plague Doctor trophy you now have to wait for a couple of days, then return to Merhojed and speak to Melichar.

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