The Uzhitz stables have lost their fastest stallion, Pie. The head groom has requested that you find him. You should begin by speaking with Vashek, the stableboy. He will tell you everything you need to know to begin the search.
Go to the crossroads south of Uzhitz, where Vashek indicated that Pie might have gone. Dismount at the crossroads and search the ground on the eastern pathway for horse droppings. Interact with them to establish the next phase of the search.
You will find more droppings along the way. Continue east and follow them along the path. When you reach a fork in the road, turn right, where you will find more droppings. At the next fork continue on to the right and follow the droppings. You will eventually reach another fork, turn right again and go down the slope.
After speaking with the wayfarer you will be able to see a highlighted area on the map, within which Pie can be found. Make your way to the highlighted area until you reach the stream. Follow the stream eastward until you arrive at an opening in the woods where Pie can be found.
The charcoal-burner seems to think that Pie belongs to him now. Speak with him and explain the situation. He will not be happy to hear that the horse belongs to the Uzhitz stables, so you will have to bribe him or beat him in a fist fight to get the point across. When you have dealt with the charcoal-burner, mount Pie and return him to the Uzhitz stables.
When you have successfully brought Pie back to the stables, speak with the head groom to receive your reward and complete the quest.