Father Knows Worst - Toussaint (Blood and Wine)
Location: West of Tourney Grounds
Quest Giver: Gran'place Notice Board
Other Requirements: Blood and Wine DLC
This quest can be started by visiting the Gran'place Notice Board. For the first objective of this quest head over to the quest marker on your map in western Toussaint to find two men who you'll speak with to update your quest. They'll ask you to go deeper into the cave to find their brother, Hugo. In the first part of this cave you'll face some Kikimores. In the same room you'll find a bunch of Kikimore eggs, make sure you Igni them to stop them from ever spawning on you.
Use your Witcher Senses to find the foot prints then follow them to Hugo who is currently sitting on top of a rock in the back of the cave. He'll ask you to find a part to his father's distillery which is hidden within this cave. In the lake that you passed by on the way here is where you will find the part (shown in screen shot below).
Once you've obtained this part you'll want to return it to Hugo. Give it to him and there will be some dialogue after which you'll exit the cave. There will be a group of "bandits" outside the cave talking to Hugos brothers and Hugo will freak out and suggest they're here to kill him. You can choose to fight these "bandits" or not, I recommend you do not as they're not actually bandits and his brothers don't want to harm him. Hugo is just a drama queen.
Either way, ask for payment when you're all done and the quest will complete.