Pestilence is one of the most important side quests in Kingdom Come: Deliverance. It starts automatically when you reach Merhojed during Questions and Answers main quest and after meeting one of the villagers. You learn about the titular pestilence. The walkthrough below has information on how to stop the plague and how to cure all the sick in Merhojed.
- Speak with Melichar about the plague in Merhojed
- Find the sick in Merhojed
- Meet with Johanka in Sasau Monastery
- Examine the disease and find its source
- Prepare the cure for the disease
- Cure the sick in Merhojed
- The ending of the quest
Speak with Melichar about the plague in Merhojed
Meet with Melichar right after learning about the problem with the pestilence and the attack on Merhojed. Don't try to force him to allow you to meet with the prisoner - he won't agree to it unless you help him with the plague. Melichar suggests you to speak with Johanka in Sasau Monastery.
Find the sick in Merhojed
Find the sick in Merhojed before you head to Johanka and take a closer look at symptoms of the disease. The houses of the sick people have white crosses on their doors but you can find them even faster by following the map above. Those people are:
Melichar's wife (point 1 on our map) - You had a chance to learn about her state during the previous conversation with Melichar.
Vincent (point 2 on our map) - Ask him every question. You can also receive a silver ring and a Will. These items are related to a small side quest called Last Will and Testament. The document needs to be delivered to Father Fabian in Sasau or you can find Vincent's son in the local inn. Deal with this quest after stopping the plague - you don't want to waste any time.
Straw's wife (point 3 on our map) - Straw isn't in a good mood. Choose the dialog line related to persuasion to calm the man down. Choosing the intimidation option can initiate an unwanted fight with Straw (it can result in his death). His wife is sick. Examine her to learn about the woman's health.
Daniel (point 4 on our map) - You can use persuasion to pretend to be his brother but this won't affect the examination process.
Bedrishka (point 5 on our map) - You learn that the plague has killed her husband. You are asked to dig him a grave. You can agree to help the woman but this will cost you a little bit of time. Don't leave this optional objective for later because it will be canceled. You can also refuse to help her or you can ask her to share information about the disease first before you dig the grave.
Meet with Johanka in Sasau Monastery
You can go to Johanka right after talking with Melichar but this isn't recommended because you will have a very limited knowledge about the disease. It is better to meet with the sick first. Johanka tells you to meet with Brother Nicodemus.
Examine the disease and find its source
Nicodemus can be found either in the infirmary or in the room with an alchemy bench.
You have to be careful while you are talking with Brother Nicodemus because some of the dialog lines can have serious consequences and prevent you from healing everyone in the village:
Tell Nicodemus that only half of the village is sick (the second dialog option).
Tell Nicodemus that all animals are dead (the second dialog line).
Tell Nicodemus that you have identified the symptoms of the disease (the first dialog option). You can choose this line only if you have met and either examined or spoke with the sick in Merhojed.
Nicodemus asks Henry if he can read:
Henry can read - tell him that you can do that and that you are willing to help him in examining the disease. This is the only way to cure everyone in the village.
Henry can't read - Tell Nicodemus about the symptoms of the disease. The monk will need a lot of time to identify the disease and to prepare a cure. In the meantime, some of the villagers can die.
Check out the book presented in the picture 1 if you have offered your help. Pick it up and read all of its pages. After that you have to go back to Nicodemus. Tell him that poisoning from water is the source of the plague (the picture 2).
Note - Choosing the wrong option won't allow you to prepare a cure fast which means that some of the villagers will die.
Prepare the cure for the disease
After selecting the right diagnosis, you have to make another important choice (see the picture). You can:
Offer your help - This is the only way to cure everyone in the village.
Tell Nicodemus to prepare the cure - He will need a lot of time. In the meantime, some of the villagers will die.
Important note - Get the required ingredients before you work on the cure. Valerian and Thistle can be bought from, e.g. Nicodemus but you have to get them BEFORE you go to Merhojed. Charcoal can be bought from, e.g. the blacksmith in Sasau.
Note - Save the game (drink a Saviour Schnapps) before you start working on the potion. You won't fail the quest if you make a mistake. However, you will waste the ingredients.
Step 1 - Approach the alchemy bench. Check the book on the right and find Merhojed Remedy (see the picture). The ingredients are 1 Valerian, 2 Thistle and 1 Charcoal. Hold the interaction button to move all the required items from the inventory to the alchemy bench.
Step 2 - Find water on the left. Pick it up and pour into the huge cauldron (water serves as a potion base).
Step 3 - Find Thistle on the right and put it into the cauldron. Repeat this action by putting another Thistle into the cauldron - there should be 2 units of this herb.
Step 4 - Star using the bellows (pull the string) to heat up the cauldron. Keep doing that until you notice bubbles on the water's surface (see the picture).
Step 5 - Find the sandglass on the right and rotate it. You have to use it to measure time. Wait for the sand to go down from the upper part into the bottom. Repeat this by rotating the sandglass again. Wait for the sand to go down again (2 times in total).
Step 6 - Find Valerian on the right and put it into the cauldron.
Step 7 - Use the bellows again until you notice bubbles on the water's surface. Interact with the sandglass and rotate it. Wait for the sand to go down into the bottom part (this time you have to do that only once).
Step 8 - Let the cauldron to cool down. The flames beneath it should disappear (see the picture above).
Step 9 - Find Charcoal on the right and put it into the cooled cauldron.
Step 10 - Find a bottle on the left and pick it up. Use it on the cauldron to pour its content into the bottle.
The quest should update and you will receive Aid for Merhojed potion (provided that you didn't make any mistakes) - the picture shows this moment. Otherwise, you have to load the last save and try again.
Cure the sick in Merhojed
Go back to Merhojed and find Brother Nicodemus. He should be in Straw's house:
Nicodemus was the one who prepared the cure - you learn who survived and who didn't make it.
Henry was the one who prepared the cure - your objective is to heal everyone.
The map above shows people in need. They are:
Bedrishka (point 1 on the map)
Daniel (point 2 on the map)
Vincent (point 3 on the map)
In addition to that you have to go to the barn (point 4 on the map) and heal the bandit (this happens after resuming Questions and Answers main quest).
The ending of the quest
Go back to Merhojed after a few days because the cure needs time to work. Meet with Melichar and receive your reward. Also, saving everyone unlocks Plague Doctor achievement.