This section of the Guide to Greedfall you will find a description of the mission Sins of Father Petrus, commissioned by the man himself.
Where to start the quest?: Talk to Petrus and complete the previous missions from him.
Talk to the friend and move to New Serene. Go now to admiral Cabral and ask her for information. Then go to Hikmet and question captain Lisandro, you will learn amazing things about the mother of the main character. Now go to the Village of Vignamri, where you will find Ullan, talk to him.
Now question the villagers, and then run to the specified location. There, you will find a woman attacked by wild animals. Kill the animals, don't kill the woman, and watch the cutscene. You will finish the side quest, gain 1600 XP and +3 rep with Petrus.