Horizon Zero Dawn's Into the Borderlands follows the previous quest, The Field of the Fallen, and there's a suggestion things might not be all they appear to be with Ersa's death.
Before long, during Into the Borderlands, you'll be off to some of the more uncivilized areas of your world, to chase down operatives and tackle Dervahl's Champion on the way to finding out more.
If you're after help for other parts of the game, consult our complete Horizon Zero Dawn walkthrough and guide.
How to find Marad's Operative
The plot thickens and we divert briefly into spy-thriller territory here, as your first proper objective after a quick brief with the Meridian royalty is to hunt down an undercover operative with info on the enemy. Here's our walkthrough of the mission:
Meet Erend at the Palace of the Sun - Head back to Meridian now and meet Erend at the Palace of the Sun.
Talk to Marad - Before you get to Erend however, a man called Blameless Marad will stop you at the Palace entrance.
Follow Marad - Follow him, up to the palace, where you'll speak to the Sun King Avad himself, along with Erend, too.
Go to Pitchcliff - Next stop, Pitchcliff, where Marad should have an Operative.
Meet Marad's Operative - Head up to where the Operative should be, and find Erend instead.
Find Marad's Operative - Time to get searching. Follow your waypoint and start scanning the village area nearby, where you'll find a glowing purple track. Follow it... until you find the Operative's body. Fortunately, it seems he managed to mark a location in the ground with his own blood. A true martyr!
Defeat Dervahl's Champion
Go to Derahl's Camp - Head to the location on your map by following your waypoint.
Kill the Outlanders and Machines - At his camp, there are several machines tied up alongside his troops. You can kill them or set them loose to attack the Outlanders themselves, it's up to you, but everything needs to be killed somehow.
Defeat Dervahl's Champion - With them out of the way, Dervahl's Champion rocks up, wielding something pretty heavy. Take him down with a series of headshots, or some damage from the Ravager's cannon if you detached it.
Find Ersa - Head into the cave that housed the Champion.
For more Horizon guides, explainers and advice, take a look at our main Horizon Zero Dawn guide and walkthrough hub, or our advice on finding Horizon Zero Dawn's override Cauldrons for controlling any machine, and unlocking some super-strong armour with our Horizon Zero Dawn Power Cell locations guide, too.
Disable the Sonic Barrier
To disable the Sonic Barrier, shoot or hit the red light on the right just inside.
Investigate Dervahl's Workshop - head downstairs and into the workshop, where you'll find Ersa locked up.
Talk to Erend - Chat with Erend after the cutscene there to tie up the mission.
So the story of Ersa is wrapped up - but the story of Dervahl is not. It sounds like he has some pretty nasty plans in store, so it's on to the next ominous-sounding mission: The Sun Shall Fall.