I managed to get a clue thanks to Fox's scent, but that's all i can get. I do not know where to progress. And I do not know how to convince the Baron to open the gate so I can leave and progress the game.
You need to visit Alexia in the Inn on the second floor. After that ask Nancy on the first floor for advice and get milk from the old woman in the northeast part of the village. Return to Alexia and give her the milk. Wait for afternoon and grab the blue bottle in her room.
Show the bottle to Father Fox and then confront Alexia. She will tell you who ordered the theft and now you can exit the village to the north, give Lui an answer to his question (last answer) and defeat Kaali. A new quest (sly fox) will be on the quest board in the village. Meet with Mother Susan at night at the graveyard outside the church and then progress with that quest.