STORY 33 - Tedd Deireadh, The Final Age
Recommended Level: 30
Objective: Follow Yennefer
And now the world is ending. Great. Just great. When the quest begins, trail after Yennefer until the fireballs start raining from the sky, prompting you both to move a little faster. Sprint through the beams and past the boat while avoiding the falling fire. You'll see the glow of where a fireball will land about a second before it does, so use this to avoid the falling flames. After a bit more running, you'll need to mount a horse. Even better, something that steers worse then Geralt.
Get on the horse and keep following after Yennefer as you wind your way past more explosions and the ongoing battle. Racing past the forces locked in mortal combat. Eventually partway up a mountain, Yennefer will dismount. Follow suit and follow the trail upwards with her until you are stopped by a snowstorm. Time for the old bubble magic again. Stay inside the bubble as you work your way up the path. A little later, a hound of the hunt will spawn in and attack. Deal with it quickly (igni and light attacks) and then another one further on.
Objective: Get to the elven tower
After triggering the scene and getting safely to the base of the tower, start climbing once again. Climb the steps and enter the tower to find Avallac'h and Ciri. You'll have several dialogue choices here that focus around sparing or killing Avallac'h and letting Ciri enter the portal or not. The choices are up to you, but they do affect the ending. Either way, once the scenes and dialogue are over so is the quest.