The Womb of the Mountain comes after one of Horizon Zero Dawn's key moments, The Proving. Aloy wakes up somewhere she's never been before, the name of which is also the name of this quest.
If you're after help for other parts of the game, consult our complete Horizon Zero Dawn walkthrough and guide.
The Womb of the Mountain
The Womb of the Mountain starts off with more of the same walking-and-talking stuff at first. Follow the waypoints as you reach them, recovering you Focus, equipment, and general bearings as you go. Then, it's time for a chat with Teersa, one of the High Matriarchs of your new tribe, which proves rather enlightening, before your skill, made apparent in the Proving, is immediately put to the test.
Search for your Focus - head straight on from where to wake up, towards a room with a closed metal door, a quick cutscene will trigger on entry, where you find your Focus.
Search for your Equipment - Next up it's time to find your bow and other items. Continue through a couple of those large blast doors and it's in a room on the left, with that other Focus emitting a signal of its own.
Follow Teersa - After watching the cutscene, follow Teersa through the network of tunnels and listen to what she has to say.
Follow Teersa out of the Mountain - Keep following! Teersa has plenty to tell you.
Talk to Resh, the new War Chief - Having left the Womb of the Mountain, Teersa tells the fellow Matriarchs that you must become a Seeker, in order to travel beyond your local lands. When that cutscene's over, go talk to Resh down below; the grumpy organiser of the Proving is now the Tribe's new War Chief.
Kill the 'Demon' and Corrupted Machines
Barely after you've spoken to him however, some particularly nasty-looking machines attack. A Corruptor is the main one, plus a couple of other smaller machines. Take out the small ones first, then focus the Corruptor. Standard damage should be used on its missile launchers on either side of its head, until they're destroyed, then Fire Arrows on its main body.
It will occasionally overheat, exposing a kind of cooling cell in the centre of its body. Hammer that with Fire Arrows until it explodes, dealing massive damage. And remember to keep moving!
Examine the "Demon" carcass - Examine the body and you'll be able to pull out the device it uses to corrupt machines... and override them yourself! Press Triangle when near an overridable machine and it'll turn to your side, defending you in battle or even letting you use it as a mount.
For more tips, explainers and advice on Horizon be sure to check out our main Horizon Zero Dawn guide and walkthrough hub, which includes advice for things like Horizon Zero Dawn's override Cauldrons and which machines they let you control, getting hold of the Golden Fast Travel Pack for unlimited fast travel, finding and unlocking the very powerful Horizon Zero Dawn Shield Weave Armour and Power Cell locations, and then for DLC players there's our main Horizon Zero Dawn Frozen Wilds walkthrough and guide, a page on how to earn Bluegleam quickly, and finally, a page on the handy A Secret Shared quest and how to upgrade your spear in Horizon Frozen Wilds.
With the corrupting machine tackled and the Override Device extracted, it's time to go test it out for yourself. Maybe you can turn machines to your own will, too? Next up, it's the mission A Seeker at the Gates.