In Dune: Prophecy, we’ve not gotten to the point where everyone in House Harkonnen shaves their head and starts loving sadism, but the series is certainly laying the groundwork for how and why the most depraved and arrogant group in the Imperium became that way. While Dune: Prophecy draws on previously established lore from Frank Herbert’s Dune (1965), it fleshes out those specifics from much newer books. In fact, the extended flashback in the third episode, “Sisterhood Above All,” focuses on a pivotal murder from the book Mentats of Dune, published just 10 years ago, in 2014.
It's in this moment, and the episode overall, that we begin to understand the long rivalry between House Atreides and House Harkonnen. Yes, House Atreides has a right to be mad here, but the beginnings of House Harkonnen probably aren’t what most fans assumed. Spoilers for Dune: Prophecy’s “Sisterhood Above All” ahead.
House Harkonnen Before Giedi Prime
At this point in the Dune timeline, House Harkonnen hasn’t relocated to the planet Giedi Prime. Instead their the homeworld is Lankiveil, a snowy planet where harvesting furry whales is a major business. Whale fur is mentioned in the original Dune, and that’s intentional: selling a ton of whale fur will actually lead to House Harkonnen being ascendent, at least in the long run. Right now, in the present tense of Dune: Prophecy, House Harkonnen has been shunned and all but exiled. This idea comes from the first episode when we’re told that House Harkonnen was blamed for having “deserted the fight” in the fight against the oppressive Thinking Machines.
In a tense dinner scene in this flashback, Vayla (Jessica Barden), hints that her grandfather was incorrectly accused of being a traitor because he “tried to stop a genocide.” What’s she talking about? Well, at the end of the episode, we learn that Valya and Tula are still using illegal AI, which means it’s possible that their grandfather wanted to preserve some intelligent AI, rather than destroy it all. That would explain the accusation of cowardice during the Bulterian Jihad — either you were for the eradication of all AI, or you were likely considered a traitor to the human race.
But, more broadly, what this episode establishes is that after the defeat of The Thinking Machines, House Atreides actively did its best to keep House Harkonnen down and out. Which, of course, is why they came back with a vengeance.
Tula infiltrates House Atreides
Elsewhere in the flashback, a little while after the tense dinner scene, but not even close to the present, we find that young Tula (Emma Canning) has also left Lankiveil, and is now pretending that her last name is “Vale.” She’s been living with the Atreides after falling in love with a man named Orry Atreides and hiding that her last name is really Harkonnen because she knows that his family won’t approve. But the twist is Tula isn’t actually there out of love for Orry Atreides, she’s there to poison him and all the members of his family. This is on Valya’s orders and explains why, in the second episode, Tula mentioned the secrets and sacrifices they’ve both made to get to where they are.
Up until this point, Valya seemed like the more hardcore of the two sisters, but in this episode, we see that Tula is capable of poisoning an entire family at the same time. She spares one of the younger kids, but that’s literally it.
Again, this event technically comes from Mentats of Dune, but there, Tula murdered Orry, not this many people. And so, in presenting this twist, Dune: Prophecy is slowly introducing the merciless nature of the Harkonnen line. They started out as victims, and then evolved into power brokers out for revenge, and eventually, ultimate power.
