Choosing to tell him more will open up another option of curing Vivienne. You can choose whether to tell him more about the curse or not. Once back at the camp, talk to Guillaume. Once meeting up with Vivienne, and finding more about her curse, head back to camp with her or by yourself. Inside the may be a Wight, they are weak against Necrophage Oil and Axii sign.
The bird will eventually fly over a hill and Geralt wishes to take a shortcut through the cave. You may encounter some Panthers on the path whilst following the bird, so using Beast Oil on your Steel sword will be useful. Use your Witcher's Senses and follow the bird. Head to Vivienne's tent, once there you'll discover she's disappeared and all that remains is a bird. Once the duel is over, Vivienne makes a speech then head to her tent. If you have chosen Ravix of Fourhorn, Tailles will confront you and you will have to defeat him and his thugs in a fist fight, however, you will not attain virtue of honor from the side quest There Can Be Only One. Choosing to accept and winning the duel, you'll attain the virtue of honor for the side quest There Can Be Only One. If you have chosen Geralt of Rivia, Anseis will confront you and you will need to have a mounted duel with him. Once the race is completed, one of the two knights will confront you depending on which name you chose when registering for the tournament. If you win the race you'll be rewarded with a saddle adorned with your crest. Next up will be the horse racing round, which will including hitting dummies with your sword and shooting targets with your crossbow to increase your time. Use your Witcher Senses to find items until the next round of the tournament begins. Guillaume will take you to Vivienne's tent to find clues to what out curse she has. Winning the crossbow round will reward you with a crossbow adorned your crest. Before it begins you'll meet a friend of Geralt who wishes to play a game of Gwent to pass the time, winning the game will reward you with an easier Crossbow shooting round. The first part of the tournament involves shooting targets with a Crossbow.