Goodness Gracious Great Balls of Granite - Toussaint (Blood and Wine)
Quest Giver: Roland or Gran'place Notice Board
Other Requirements: Blood and Wine DLC
To begin this quest visit Roland (pictured above) or the Gran'place Notice Board; if you visit the Notice Board the first step of your task will require you to speak with Roland. For this quest you'll need to follow Roland to the crime scene where you'll have to use your Witcher Senses to locate a piece of fabric caught on a nail.
Go down the northern stairway next to the statue to find a piece of fabric caught on a nail (it's on the wooden fence). Inspect this to acquire a scent trail which you'll need to follow through town. Tip: If you're having trouble seeing the scent trail during the daylight rest until night. It'll be much easier to follow.
The scent trail will end at a house that is a tad bit west of the Gran'place Notice Board (exact location shown on my map below).
At the house there will be a funny scene, during which you'll be interrupted by another man. You can use Axii on him or fist fight him, it doesn't matter. As for Hughes, you have three different choices and depending on what you choose you'll get a different virtue for the quest There Can Be Only One.
1. Lend Hughes the testicles - Honor Virtue
2. Let Hughes keep the testicles - Compassion Virtue
3. Take the testicles back to the art dealer - Honor Virtue
Note: If you lend hughes the stones then you'll have to wait to turn in this quest, until you get the stones back. Also Hughes will die from overexertion if you choose this option.