This guide is a walkthrough of a main quest of the Witcher 3 in the area of Kaer Morhen. The guide is composed of a map, map legend, and walkthrough to show readers exactly where to go and what to do to complete the quest.
Walkthrough
After tracking down Ciri (in The Isle of Mists) and recruiting some allies (in Brothers in Arms), when you return to Kaer Morhen you’ll find everybody there waiting for you. If you want, you can talk to a few people, but most of these conversations won’t lead to anything. However, Zoltan (found in the outer courtyard by some red, explosive barrels) will repair your equipment, and Keira Metz (found just inside the entrance to the inner keep, #1) will sell you glyphs and runes if you talk to her twice — provided you didn’t kill her earlier.
Note: Keira might be buggy. If you get “stuck” in conversation with her after doing some shopping, it’s because the game is waiting for you to make a dialogue choice even though it’s not showing you any conversation options. To fix the problem, just press the down arrow and then press enter. That should select the “See you, Keira” option and let you leave.
When you proceed far enough into the inner keep (#1), you’ll start making plans for the upcoming battle. Most of these plans are fixed, but you’ll have to make two decisions:
- Laboratory. If you choose potions, then you’ll receive
Superior Swallow, 
Thunderbolt, a 
Lesser Perun Runestone, and 50 xp. (We’ve heard people say that you should receive 
Enhanced White Raffard’s Decoction instead of Thunderbolt if you completed the quest Following the Thread, but that wasn’t the case for us.) If you choose traps, then Eskel will automatically place some traps around the courtyards of the keep, which will damage the Wild Hunt for you. But be careful. Only the Wild Hunt will be able to trigger the traps, but they’ll still hurt you if you’re nearby, and they might also set off gas pockets or explosive barrels, which might inadvertently damage you as well.
- Workshop. If you choose the armory, then you’ll receive a leveled version of the silver sword Rose of Shaerrawed, and the other witchers will deal more damage. If you choose to patch the wall, then you’ll face fewer enemies at the end of the battle when you have to fight inside the inner courtyard.
Regardless of your choices, you’ll earn 500 xp at the end of the planning stage. Then to start the battle, you’ll just need to exit the inner keep.
Battle Stage 1: Forest
You’ll start the battle with Lambert (and possibly Letho) in the forest south of Kaer Morhen. Wild Hunt warriors and hounds won’t be able to teleport directly into the keep’s grounds thanks to Yennefer’s magical barrier, but they will be able to arrive in the forest via three portals. So you’ll need to destroy the portals (#4).
When you’re not fighting or near hounds, you’ll be invisible — again thanks to Yennefer — so move right up to one of the portals, defeat Wild Hunt defenders as necessary, and then use Yrden or a 
Dimeritium Bomb on the portal to destroy it. Since defenders will just keep appearing until you destroy the portal, you should focus on the portal first and then mop up whatever’s remaining.
When all three portals have been destroyed, the Wild Hunt commander Imlerith will arrive and your invisibility spell will disappear, but when you signal Triss to rain down some fire on the enemy forces, nothing will happen. Still, you’ll receive 700 xp for completing the stage.
Battle Stage 2: Ramparts
For this stage, you’ll be in control of Ciri, and you’ll be tasked with assisting Triss. You’ll find her just to the south. You’ll have to defeat the few Wild Hunt warriors and hounds harassing her, but after that she’ll be able to get to work and start raining fire down onto the forest.
Battle Stage 3: Retreat
Back with Geralt, when the fire starts hitting the forest, you’ll decide to retreat back to Kaer Morhen. Conveniently, Roach will be right there, so you’ll be able to ride him for the trip. Triss’ fireballs will hurt you if they happen to connect, so try to ride back quickly. The fireballs should land behind you if you keep moving.
When you reach Kaer Morhen, you’ll discover that the fighting has breached its outer walls, and Vesemir will call out for you to close the outer gate (#3). To reach the gate controls, you’ll need to climb up to the ramparts and then make your way to the gate lever (located just above the gate), killing whatever Wild Hunt forces get in your way. When you pull the lever, you’ll be just in time to keep Imlerith outside.
At this point Vesemir will order everybody to retreat to the inner courtyard (#2). However, when you reach the courtyard gate, you’ll find it closed, with no Eskel around to open it for you. So you’ll need to head to the northern part of the outer courtyard and help out with the fighting there. Once the area is clear, Triss will signal to Ciri on the ramparts to go help Eskel.
Battle Stage 4: Eskel
Back as Ciri, you’ll discover that Eskel is fighting — and losing — against the Wild Hunt commander Caranthir, but then Caranthir will get called away, and you’ll only have to deal with a few Wild Hunt warriors. Ciri will automatically regenerate her health, so if you get into trouble, then just start teleporting around until you’re ready to fight again. Otherwise, the easiest way to deal with the warriors is to keep teleporting behind whichever one Eskel is fighting, and finish it off with a few quick swings from your sword. You’ll also have Triss’ amulet at your disposal, which can call down fire at your position.
Eventually you’ll fight your way over to the inner courtyard gate. Once the courtyard is clear, you’ll just need to interact with the gate wheel to open the gate and allow everybody to retreat inside.
Battle Stage 5: Inner Courtyard
Back as Geralt, you’ll be in the inner courtyard, but with Yennefer’s magic waning, the Wild Hunt will put up two portals nearby. So you’ll have to destroy them, just like the portals in the forest. Once again the Yrden sign or a Dimeritium Bomb will do the trick, and Vesemir will give you two Dimeritium Bombs just in case you need them. If you take too much damage while dealing with the portals, then you should just run back to Ermion in the middle of the courtyard. He’ll have a Circle of Vitality around him, which will heal you quickly when you’re inside it.
Unfortunately, once you’ve destroyed the portals, Yennefer’s magic will finally fail, and the Wild Hunt forces will blow through the inner courtyard gate, freezing you in the process. With your side in disarray, Caranthir, Imlerith, and the Wild Hunt leader Eredin will corner Ciri and Vesemir. Ciri will try to give herself up to save Vesemir, but Vesemir will sacrifice himself instead. Ciri will then release a tormented scream of magic that will drive the Wild Hunt forces away and teeter towards killing you and your allies and destroying the keep, but Avallac’h will rise up from his sickbed and magically knock Ciri out, ending the threat.
When Ciri falls unconscious, you’ll complete the quest and earn 1000 xp. Then with the danger gone, the remaining defenders will take the time to recuperate and give Vesemir a proper funeral. But Ciri will be heartbroken, and she’ll decide that she’s had enough with hiding and fleeing.
