Aphelion: Chapter 3 & 4 Walkthrough – Escape Pod to Onyx Forest

Chapter 3 opens with one of Aphelion’s nastiest little tricks: Thomas wakes up hurt, the cave walls look climbable, and the obvious line forward is the wrong one. This walkthrough covers the clean route through Chapter 3 “The Escape Pod” and Chapter 4 “The Onyx Forest”. Treat both as survival traversal, not freeform exploration. The catch most players miss is that these two chapters are not even the same character: Chapter 3 puts you in control of the injured Thomas, and Chapter 4 switches back to Ariane and her full traversal kit.

The short version

• Chapter 3 “The Escape Pod” is Thomas, injured. Linear survival traversal through a cave. Refill oxygen at every tank, take offset ledges instead of forcing vertical climbs.
• Chapter 4 “The Onyx Forest” is Ariane. Cross the geyser field one vent at a time, use every winch point, scan Anomalies with the EM scanner, and stay quiet for the Nemesis encounter.
• Geysers: watch one full cycle, cross right after a burst, treat each vent as a separate timed lane.
• Winch points are mandatory, not scenery. If the path ahead looks awkward, you skipped one.
• Nemesis is the stealth threat. You hear it before you see it. Move in short bursts; audio cues beat sprinting.
• Chapter 4 ends by arriving at the outpost, which leads straight into Chapter 5 “The Outpost”.

Chapter 3 walkthrough: The Escape Pod (Thomas)

Your only real job in The Escape Pod is survival. Thomas starts injured and low on oxygen, so the chapter is less about puzzle solving and more about reading the cave the way the game intends. The path is linear, but it disguises that linearity by filling the area with climbable-looking rock that you are not supposed to commit to. If a route demands a long, exposed ascent with no clear handhold chain, back off and scan the sides for a gentler sequence of ledges.

This is also where Aphelion teaches you Thomas’s limits. His injury means he cannot traverse the way Ariane does in the earlier chapters, so the restraint you learn here is the whole point. (If you skipped ahead, the Chapter 1 and 2 walkthrough covers Ariane’s baseline traversal.)

From the crash site to the first refill

Push forward through the cave and keep your focus on oxygen before collectibles. Chapter 3 is a bad place to get greedy, because the low-oxygen pressure makes detours expensive. Follow the narrow route through the cave interior, slip through the tighter gaps when the path pinches, and look for the first climb that angles around the rock rather than straight up it. That is the recurring pattern of this chapter: the correct path wraps around obstacles instead of overpowering them.

When you reach an oxygen tank, refill even if you still have reserve. Top off early, because the next traversal test often sits immediately after a refill. Saving a few seconds by skipping a tank is not worth replaying the last few minutes if the next platform chain goes badly.

Rocky ledges, gap squeezes, and the waterfall section

The middle stretch is where most wasted time happens. You move across rocky ledges, squeeze through gaps, and eventually deal with the cave’s waterfall-heavy section. Think in short climbs. Do not stand at the base of a wall and try to read the entire route in one look. Identify the next handhold, the next safe ledge, and the next oxygen source, then move. Aphelion rewards that incremental planning.

At the waterfalls, surface readability gets worse. If the water makes a route hard to read, step back and look for a side angle rather than walking under the spray and hoping a climb prompt appears. The correct line stays deliberate and leads upward toward another oxygen refill. Once you reach a pull-down bridge, drop it immediately. Even when the bridge feels like a one-way convenience, it anchors your sense of direction in a chapter that keeps curving through similar cave spaces.

Reading the chapter ending

The end of Chapter 3 is about paying attention rather than execution. As you push through the final route, the environment starts telling a story through equipment and traces left behind. That organized trail is the chapter’s tonal shift, and it explains why the cave suddenly feels less like a random disaster zone and more like a place someone passed through with intent. Once the closing cutscene hits, the lesson is clear: Chapter 3 was training you to stop improvising and trust Aphelion’s authored route language.

Chapter 4 walkthrough: The Onyx Forest (Ariane)

The Onyx Forest picks up right after that story beat and hands control back to Ariane, so you regain the fuller traversal kit you had before the cave. The chapter broadens the challenge without becoming open: it mixes cave-exit traversal, environmental hazards, winch points, ledge chains, Anomalies, and stealth. It feels more hostile than Chapter 3, but it is fairer once you see that every obstacle has one dominant idea: timing for geysers, interaction for winches, scanning for Anomalies, patience for stealth.

Exiting the caves and crossing the geyser field

The geysers are the first thing that makes players rush, and rushing gets you clipped. Watch one full cycle before you move into a dangerous patch. Cross right after a burst, not during the moment it looks like it might be fading. Treat each vent as a timed lane: clear one safely, reset your view, then commit to the next. Chaining the whole field in one sprint is riskier than it looks.

After the geysers, the chapter returns to smaller climbs. Follow the ledges that step Ariane across the terrain rather than up it. If the route seems to vanish, check for a side ledge or a point where the path folds back on itself. Aphelion favors layered routes that read more naturally from the side than from directly below.

Winch points and route control

Whenever you reach a winch point in The Onyx Forest, interact with it before wandering off. Winches stabilize the route, open the next climb, or create a safer traversal angle. The common mistake is spotting the destination first and treating the winch like optional scenery. It rarely is. If the path ahead looks awkward or too exposed, you missed a winch interaction that makes the intended route obvious.

EM scanner, Anomalies, and the Nemesis stealth beat

When progress stalls around odd environmental distortion, unfamiliar equipment, or a space that feels deliberately staged, pull out the EM scanner. Chapter 4 uses scanner logic to turn confusion into direction: you are not just hunting a glowing objective, you are confirming that the environment itself is the clue. In practice that means slowing down in strange areas and scanning the Anomalies instead of climbing past them.

The stealth threat here is Nemesis, and it works on the same principle. Nemesis is usually communicated by sound and tension before you get a clean visual read, so treat it as an audio encounter first. Move in short bursts, stop when the area sounds more active, and resist the instinct to dash just because you are nervous. Slow movement keeps your options open; fast movement commits you to bad cover and bad angles. If you fail here, the fix is not faster reflexes, it is giving the encounter more respect than a normal traversal segment. Nemesis returns later in the game, so the habits you build now pay off again in the Chapters 7 and 8 walkthrough.

The last stretch to the outpost

Once you are through the scanners, hazards, and stealth pressure, the final route is mostly clean execution. Stay disciplined on the ledges, use any last traversal interactions as soon as they appear, and do not turn the closing path into a scavenger hunt. Chapter 4 ends by bringing Ariane to the outpost, which leads directly into Chapter 5 “The Outpost”. After the uncertainty of the caves and forest, that arrival reads as progress in the story as much as in the level flow.

Common mistakes in Chapters 3 and 4

• Skipping oxygen because the tank looks “close enough.” Refill anyway in Chapter 3.
• Climbing straight up in Chapter 3. The correct path is offset to one side.
• Crossing geysers on instinct. Wait for a full cycle and move after the burst.
• Ignoring winch points. If the route ahead feels clumsy, the winch was required.
• Forgetting the EM scanner exists. Chapter 4 expects you to scan Anomalies, not only climb.
• Treating the Nemesis encounter like a chase. Audio discipline beats panic movement.

Practical takeaway

Chapter 3 is about surviving with Thomas’s limited mobility; Chapter 4 is about using Ariane’s full kit to push through geysers, winches, Anomalies, and Nemesis with restraint. Top off oxygen as Thomas, trust offset ledges, use winches the moment you reach them, scan suspicious spaces, and slow down for Nemesis. Do that and The Escape Pod plus The Onyx Forest stop feeling cryptic and become one of Aphelion’s strongest back-to-back stretches instead of a pair of bottlenecks.