Time for another detailed and spoiler-laden discussion of a Knights of the Eternal Throne chapter. We're up to chapter four! Though if you missed it...
The Gravestone and the Eternal Fleet are in hyperspace on their way to an unknown destination. Officially you are in command again, but the hyperdrive is locked and you can't really do anything. When the Gravestone drops out of hyperspace, Scorpio leaves on a shuttle and tells you that you've been brought to the place where she, the Gravestone and the Eternal Fleet originated. However, Vaylin and her remaining soldiers are still on board and sabotaging the ship, which requires you to go on a clean-up mission. Meanwhile, the Gravestone continues on her course into her home world, which is a giant Dyson sphere. However, while you are off to repair the omnicannon, Vaylin overwhelms the companions you left on the bridge and taunts you by threatening their lives. Before you can take any steps to fight back, a blinding light overwhelms you and you pass out.
You awake on the inner surface of the Dyson sphere, which has a post-apocalyptic look to it: technologically advanced, but covered in moss and with plant overgrowth everywhere. A strange diamond-shaped device decides to follow you around and basically serves as your temporary companion while you are unable to raise anyone on the comm. You wander around the largely abandoned area for a bit, only encountering "custodian" droids occasionally, some of them hostile, some of them neutral. There is a bonus mission here to access various "technoliths" around the area which teach you that the "planet" is called Iokath and that its former rulers enjoyed building experimental war machines. They also appear to have been very long-lived or at least good at thinking on a grand scale, as their experiments are described as stretching across millennia and involving the casual annihilation of entire civilisations.
One technolith presents you with a talking hologram that introduces itself as Aries and offers to provide you with more information but constantly seems to encounter errors when trying to do so. Torian shows up behind you, confirming that he had a similar experience to yours, passing out from the bright light and then waking alone on the surface. You also encounter some Knights of Zakuul fighting droids, presumably having been transported down from the Eternal Fleet, and get tasked to kill the lot of them... before you get any ideas about possibly wanting to co-operate with them in such a strange and hostile environment. Theron manages to reach you on the holo and informs you that he's found a safe place to gather. He also warns you however that since everyone seems to have been transported to the surface, it stands to reason that Vaylin must be about somewhere too.
The all-knowing player behind the keyboard is not kept in suspense for long, as we then cut to a shot of Vaylin waking in what appears to be something like a padded cell, only without the padding. She quickly gets angry about her imprisonment and starts using the Force to tear at the walls... when suddenly, he dead brother Thexan appears out of nowhere and tries to calm her down. Vaylin is wary of him but certainly distracted.
You meet with Theron, who's managed to get the rest of your crew together. He's been trying to find the Gravestone but his cybernetic scanners only go so far. You get a chance to talk to your remaining companions here - no proper cut scenes, but a little bit of dialogue voice-over plays when you click on them. Several of them express a feeling that you are being tested by being separated and placed in a strange environment. Vette has activated another technolith in the meantime and got Aries the hologram to tell her more about Iokath - basically the cliff notes of the codex entries you might already have uncovered earlier. It's also revealed that Zakuul was one of the worlds that was being experimented on.
A cut reveals Vaylin talking to Thexan some more, clearly torn between affection for her dead brother and scepticism about why a dead person would suddenly appear in front of her. Your chat with Aries is suddenly interrupted by Scorpio appearing on the holo. She confirms that you're all being used as test subjects and suggests working together to escape. You get interrupted once again by a bunch of droids storming your shelter, which you then have to fight off. After a drawn-out and annoying fight, Theron has the bright idea to shoot a panel that causes a force field to go up and prevents any more droids from coming in. Why couldn't you have thought of this earlier, Theron?
Vette fiddles with the technolith some more and almost accidentally opens another door. You don't know what lies behind it, but it's gotta be better than all those purifier droids, right? You eventually find another technolith, and realise that it's surrounded by lots of little capsules which appear to form a crypt for Iokath's creators. Through it, Scorpio manages to contact you again and tells you of how Iokath's own creations turned against their creators and killed them, though their memories were locked so they couldn't remember their origins.
We also see Vaylin trashing her cell and escaping, after having tricked "Thexan" into revealing that he's not really her brother. Turns out the one hiding behind Thexan's face was no other than Aries, the hologram that shared information earlier - he's not just a hologram, but another AI created by Iokath's founders, and now also the one in control of this entire world.
Most of KotET's chapters stand pretty well on their own, but chapters four and five are very closely tied together, with chapter four being pretty much a set-up for everything that happens in chapter five. Because of that, not much really happens in chapter four! There isn't even a single dark/light or otherwise story-defining choice to be made here. However, I didn't even notice that myself until someone else pointed it out to me, because I was too busy admiring the pretty scenery. The overgrown parts of Iokath in particular are very good at creating an appropriate atmosphere and look beautiful to boot.
While the matter of the Gravestone, the Eternal Fleet and Scorpio's origins had come up repeatedly during Knights of the Fallen Empire, I have to admit I was kind of surprised to find KotET devoting two whole chapters to it, especially at this point. It all comes a bit out of left field and only has a fairly tenuous connection to the rest of the story in my opinion. I'd rather they had saved this particular plot thread for later and instead incorporated the scions into KotET somehow - they were one story thread that originally felt very important but then just vanished completely.
Anyway, even though the chapter's main purpose is to introduce you to Iokath and there isn't much else to it, I quite enjoyed it because Iokath is simply a fun place to be, which adds another reason to be excited about patch 5.2 (when we will return there).
Another interesting point to note is that even though both you and your companions as well as Vaylin and her subjects basically get trapped by a force more powerful than both of you here, this isn't used as an opportunity to allow both sides to find common ground or even form as much as a temporary truce. When you run into the Knights of Zakuul fighting droids, you just kill them both. At your temporary base, if you have Koth with you, he will say that a Zakuulan wanted to surrender to him but died to the droids before they could make it back together. Despite of the sheer magnitude of what you discover on Iokath, the story makes it very clear that you're supposed to still consider Vaylin your primary problem.