Important - Don't start this quest until you complete all side quests in White Orchard that you currently have in your journal. Otherwise some of them will be canceled and considered as uncompleted. You must also know that starting this quest means leaving the orchard and moving to royal castle.
It's a very short quest activated after completing the main quest Lilac and Gooseberries. More specifically, it starts after meeting Vesemir in tavern in White Orchard Village after killing the griffin and learning of Yennefer's whereabouts. After the talk, a brawl will start in the tavern. Geralt and Vesemir will have to defeat a small group of bandits. When the battle start, try to defeat enemies one after another, don't let them corner you. After the battle is won (300 experience points) the game will activate a cutscene in which you meet Yennefer and the action will move to Royal Palace in Vizima. New quest will start there - Royal Audience.