Outer Wilds guide: Find Chert on Ember Twin and explore the Lakebed Cave

Many of the Outer Wilds mysteries we’ve explored so far have eventually pointed us to the Hourglass Twins, specifically the Ember Twin. There’s a lot to explore here, and not a lot of time to do it, so let’s start simple.

This guide will introduce you to Chert, and then we’ll explore the nearby quantum caves, and the Lakebed Cave.

Table of contents

• A note about sand
• Find Chert’s Camp
• Quantum caves
• Lakebed Cave
• Cave Shard
• What have we learned? // What’s next?

A note about sand

Exploring the Ember Twin is dangerous. Over the course of a time loop, the Ash Twin pours sand onto the Ember Twin. On the surface, there’s not much to worry about, but underground — where most of what you’re here to learn lies — the sand will trap you in tunnels and eventually crush you.

This means you only have a few minutes to explore some areas.

You’re going to die while exploring here. Kind of often.

Find Chert’s Camp

Mobius Digital/Annapurna Interactive via Polygon

When you first arrive, check in with the local expert at the north pole. Follow your signal locator to Chert’s drums. Depending on his mood and how quickly you get to him, Chert will either just keep reminding you that the sun is dying, or give you a lot of useful information about the planet for your ship’s log. He’ll point you to Escape Pod 2 at the south pole and hint at an underground settlement.

A quick note: Chert will say that the sand eventually drains off of Ember Twin. While this may be true, it doesn’t happen within the bounds of a time loop, so you only have one shot at the lower levels of the planet.

While hanging out with Chert, you’ll also get an alert that there’s an unidentified signal nearby. If you pull out your signal locator, you’ll see that it’s a quantum fluctuation. Let’s start there first.

Quantum caves

Mobius Digital/Annapurna Interactive via Polygon

To the left and right (east and west don’t mean much at the north pole) of Chert’s Camp, you’ll see two cave entrances lined by Nomai columns. You won’t be able to see them when the sand gets too high, though.

Head into both of these caves to find the wandering Cave Shard and some Nomai script. The script will mention the disappearance of a Nomai named Coleus from the Lakebed Cave at the north pole. Let’s find it.

Lakebed Cave

You have to start your search for the Lakebed Cave very early in a time loop — it fills with sand and disappears within just a few minutes.

From Chert’s Camp, drop off the edge and descend as far as you can. When you reach the dry lakebed, look for a cave in the ground that leads down.

The path through the Lakebed Cave is confusing and complex — and, if you take too long, you’ll get crushed by rising sand.

Your first goal is to find a sand waterfall (sandfall?) not too far in. Make sure your flashlight is on, and keep firing your scout nearby to light up the area. The path isn’t exactly clear, but the tunnels you take are left, left, left, right, left. (We think.) Use the video above — mistakes and all — to help guide you.

Mobius Digital/Annapurna Interactive via Polygon

Walk through the sandfall, and start climbing with your jetpack. On the first ledge you reach, turn around. Use your scout to light the tunnel ahead of you.

Use the rocky ledges as stepping stones, and just keep following the sandfall up. You’ll eventually reach a cave on your left. Head inside to find another small sandfall. Step through again.

Mobius Digital/Annapurna Interactive via Polygon

For the next section, your path is generally left and uphill. The tunnels will be blocked by cactuses and stalagmites a lot, but they behave like quantum objects. Turn away and check back until your path is clear.

You’ll eventually reach some stone ledges that lead up to a cave. Step through one more sandfall to enter it.

Cave Shard

In this final cave, you’ll find notes from Coleus’ friends, and a light switch. Read the notes, turn on the lights, and then spin around until the Cave Shard appears.

Plant your scout nearby, and make sure the camera is pointed at the Cave Shard. Turn out the lights, and jump across until you’re standing on top of the shard. Recall your scout, and then turn off your flashlight.

Mobius Digital/Annapurna Interactive via Polygon

In the dark, the Cave Shard will take you with it when it travels. In the cave that it takes you to, check for the Nomai script where you’ll learn a new quantum rule: When a conscious being is in contact with a quantum object and ceases to observe his or her surroundings, the being can become entangled with that quantum object, and they both move together.

Wait for the Cave Shard to come back (by looking around), climb on top of it, and turn off your flashlight. It will transport you back out — probably into one of the quantum caves you explored earlier.

What have we learned? // What’s next?

The biggest thing is that we’ve picked up a new quantum rule. Depending on how long you took exploring the cave, you might not be able to do much else on the Ember Twin. There are still a couple things to check out, though, namely Escape Pod 2 and the underground settlement that Chert mentioned. If the sand is filling up too fast, you’ll have to check those out next loop.