This chapter contains a complete walkthrough for the quest Queen's Gambit. Here you will find advice that will help you to complete this mission in the best way possible.
Beginning the quest
The quest will appear in the journal after you speak to Vanasha at the end of the quest Traitor's Bounty. The woman is planning to transport the royal family from Sunfall to Meridian. Aloy will help her in the operation.
First, you should go to the place marked on the map. There you will find Three-Toe Huadiv, with whom you must talk. You will learn that there is a Rockbreaker on the path that is supposed to be the road to Meridian. You must defeat the machine.
It won't be an easy task. The machine will ignore you until you get too close or attack it. A good idea is to use freeze arrows and bursting arrows. This will enable you to first slow down the machine and then get rid of its limbs, making it impossible for it to hide underground. Then you should use regular arrows to cause an explosion of the tank on its belly. You can also keep freezing it if that helps.
Once the fight is over, go back to Huadiv. A longer cutscene will start.
Then you must place a few traps for the incoming cultists and their machines. While the first two phases of the fight are very easy, they will end with a Thunderjaw appearing. In his case you must remember he is very vulnerable to fire. During the first phase of the battle you will be accompanied by two guards, but they will quickly die.
Vulnerability to fire will help you, but don't forget that you must destroy the disk launcher of the enemy. Keep setting the opponent on fire and take advantage of the open space.
Finishing the quest
Once the fight is over, go to the coast to continue the quest. After a long cutscene the quest and the plot of the Meridian refugees will end.