In previous Chapter 11 Return to the Summit Kratos and Atreus return to the summit to enter into the realm of giants. But after getting attacked by Baldur both are pulled into Helhiem. In Chapter 12 Escape from Helhiem, both father and son have to escape the place as soon as possible.
Escape from Helheim Walkthrough
Find a way out of Helheim
The place where you landed, you can climb up from the left wall. Go up and on your left, you will be able to climb further up, an area where you will be attacked by Hel-Reaver Guard. Go left, towards the next tower, lift the metal bridge up. After watching the shadows, climb on the right column, and move to the outer side. Keep moving left and go down towards the next stone platform below on the left with a locked door.
To unlock the door first take the wind trap and use it on the left ball first. Use your Axe to free it and then use it on the right ball. Behind that there will be a guard with a sword, he is pretty strong. Stay away when he pierced his sword into the ground. Also when he raises the skull he can release an explosion that you have to doge. Kill him will reward you Chaos Flame a Legendary upgrade for Blades of Chaos. Once again lift the metal door, to move ahead. You will spot Baldur ahead, jump ahead to hang and climb slowly towards the right. Follow the cracks to move on top and go down keep climbing through the wall to the right end of the area.
You will reach near a huge boat. Go down from the left corner and jump down on the boat. There will be few enemies ahead, clear them up and go to the towards the ship.
Use the Ship
Clear all the tree sap on the ship by using the blade, there is a wheel at the right end, rotate that to lift the sails. The ship will start moving, look for a wooden block, break it to lose the sail. Next, go to the wheel and rotate it once again, the ship will float in the air. The ship will stop on a platform, go straight and then look on your left for a wheel, as move it the stone platform will break and the boat will go up. To return to the boat, walk between the statues, and hit the rotating platform with Axe to go up and back on the boat. Next, you will have to push the second stone platform to release the ship.
Escape Helheim
There will be few enemies you have to fight with on the ship, after that you have to pull out the anchor which is blocking the ship. More and more enemies will spawn on the ship and there will be three more anchors. Clear out the enemies and release the anchor to continue. There are one more harpoon and an Ogre boss which is the final wave of the fight.
One Kratos and Atreus lands on the Secret Chamber of Odin, take the door on the right which is locked. Use the chisel to unlock it and there is another door inside. Cross that, on the left, there will be a broken part of the shrine. This completes the Chapter 12 Escape from Helhiem. You can read our walkthrough of Chapter 13 A Path To Jotunheim where Kratos and Atreus go to the dwarfs to find a key that can lead them to the realm of giants.
For more updates and tips on the game, you can refer our God of War Wiki guide.