Foundation season 3 ending explained: Cast break down shock Mule twist

The epic final instalment has been a long time coming. Previously, season 3 showed Gaal (Lou Llobell) gearing up for her inevitable battle with the Mule (Pilou Asbæk - or so we thought), while the Cleons grappled with the knowledge that Empire was about to fall - they just didn't know it would be at the hands of one of their own.

We've seen revelations, betrayals and major twists that have set the stage for what's to come if the show is confirmed for a season 4.

Complete with some intel from Gaal actress Lou Llobell and, of course, Bayta actress Synnøve Karlsen, here's everything you need to know about how Foundation season 3 ended. Buckle in!

Foundation season 3 ending explained: Who is the Mule, actually?

In a stunning departure from Isaac Asimov's book, season 3's finale unveiled Bayta Mallow (Synnøve Karlsen) as the Mule.

That's right, the apparent social climber has been pulling the strings all along, with Asbæk's character acting as a facade.

Speaking exclusively to RadioTimes.com about that shocking reveal, Karlsen says: "Knowing that there was this twist that was going to come, it just made her even more of an exciting character.

"I think she can come off slightly kind of thoughtless or careless at the beginning so once I found that out, it was such an exciting element for me."

Fans will no doubt notice the twist is wildly different to Asimov's novel, in which the balladeer Magnifico (Tómas Lemarquis) is revealed as the Mule, with Karlsen explaining: "I think that they wanted to subvert it.

"I think it's just quite interesting that it's a woman, and I guess there is something about changing something from the original to surprise people, keep people on their toes."

As for any clues she dropped throughout the season? "In episode 9, I think there is a really key moment with Dawn in the hospital bed.

"I think in that scene, [Bayta] could get away with quite a lot, because Dawn is also so out of it, and he's coming back from this epic journey and injury that he's had so she could get away with being a bit more explicit. I think if you watch that back, once you know, that'll be very obvious.

"There are a few moments, but it's not like she's some evil genius either, which is interesting. In all these scenes that she's in, it's genuine - she's acting towards this genuine goal, and she's also finding everything quite funny.

"She's genuinely in love with Toran [Mallow, played by Cody Fern], so it's not like it's she's lying to everyone all the time. It's just there's something that she hasn't quite said."

So, how did we get here? The episode begins with Gaal, Pritcher (Brandon P Bell) and co gearing up to assassinate the Mule. In her narration, Gaal says she's built her mind to be a fortress - with everyone she's lost, from Hari to Salvor, being the walls to that fortress.

As they arrive to face the Mule, Hari distracts the armed guards and Gaal hides herself, Pritcher and co from view, sneaking away to find the Mule, who they can sense is located in Indbur's office.

Han splits off from the group to try to save who he can (including, ironically, Bayta), leaving Gaal to fight the Mule. Meanwhile, Bayta manages to escape, and is forced to leave Dawn (Cassian Bilton) behind due to the injury to his legs. Bayta encounters Pritcher, who promises to help her escape - but he soon realises the Mule is close and falls to his knees as his mind is taken over.

Elsewhere, though, finally Gaal and Asbæk's Mule come face to face as he tries to get inside her mind and taunt her for information on the Second Foundation's whereabouts. Gaal fights against him but the Mule pins her down, choking her.

But, as she pointed out, her mind is a fortress. She taunts him right back, telling him how he has only ever manipulated people and forced them into loving him. She manages to escape his clutches, and slits his throat. The Mule is dead! Right? Wrong!

Gaal soon realises that something's wrong - that she can still feel someone in her head, meaning the Mule isn't dead. Suddenly, she falls to the ground, with her mind being taken over once again, and the true identity of the Mule is revealed, as Bayta walks in.

"There were so many iterations of that [scene]," Karlsen explains. "It just got shortened and twisted and changed," adding that the final cut was the scene in its simplest form.

Bayta puts Toran to sleep as Pritcher, who is under Bayta's control, fights Gaal and shoots her in the stomach.

Bayta attempts to convert Gaal, ordering Magnifico to play to amplify her powers - but his music if off-key and Bayta's powers are thrown off, with Gaal revealing that she "tampered" with Magnifico, adding: "He only plays my song now."

Thankfully, Gaal has an escape plan. She throws herself out of the window of the ship, with Rasik manoeuvring the Beggar's Belief and opening its doors to allow her to fall inside. There, she meets Hari (Jared Harris) who says he tried to warn her about Bayta.

But Hari also wants Gaal to free him from the Vault. In explaining why that can't happen, she's forced to admit that the real Hari is dead and has been for some time, and that she's been lying to him. The ship jumps, and Gaal has officially escaped the Mule - for now.

Llobell tells RadioTimes.com: "She obviously has been talking about contingencies throughout - the whole Second Foundation is a Plan B. It's a back-up. [Her escape] is her back-up in that moment.

"The whole conversation that she shares with Demerzel, it's kind of an ode to that... She's thought ahead enough to escape, but I think she didn't expect The Mule, so it'd be interesting to see what she comes up with after this."

So what could be next for her? Llobell has no inside intel as season 4 has not yet been confirmed, but she can make some guesses like the rest of us, saying: "She's off on the Beggar's, she doesn't know where the Second Foundation is, and now has a new Mule to deal with, and she doesn't really know the powers of this one.

"Now she has to reassess everything that's happened."

What about Bayta? "She's not so happy, not best pleased with that!" Karlsen says of Gaal's escape.

"[Bayta] has one goal, and it's for the sake of a whole of humanity. I think she truly believes that if everyone is kind of under her control - that's a strong word that she wouldn't use. But [she believes] if everyone is acting towards the same shared goal and purpose, they will be sincerely happy.

"I think she will stop at nothing to try and make that happen. So it'll be interesting to see how that potentially plays out."

Why did Dusk kill the Cleons and Demerzel?

The other horrifying thread that culminates in episode 10 is Brother Dusk fighting against his own mortality - which leads to him killing every other Cleon clone in existence as well as Demerzel.

We've already seen him murder entire planets with the Novacula, the black hole bomb - but the season 3 finale sees him finally destroy Empire once and for all.

The beginning of the episode sees Dusk (or, as he takes on his new moniker, Darkness) preparing to die, as his lifespan has come to an end. But he's not giving up that easily.

He makes his way to the clone tanks and, with the press of a button, blows them all up and brutally tears apart every Cleon there, blood dripping on his face and body parts gruesomely falling around him.

The one Cleon that Dusk saves from the massacre is a baby. But he has even more nefarious plans for him, taking him to where Dusk is due to be euthanised with a beam of light. Demerzel senses something terrible is happening and her programming forces her to intervene.

As Dusk places the baby down, ready for the beam to kill him, Demerzel's programming forces her to throw herself over him. While she saves the baby, Demerzel burns up in a fiery blaze - and there's nothing Day can do to save her.

Dusk then picks up the Prime Radiant from Demerzel's remains, remarking that it's made of strong stuff, as he leaves Day sobbing on the ground behind him.

Before she dies, however, Demerzel saves Ambassador Felice Quent, telling her to present a book to the librarian in the Trantor Library - which in turn, leads her to the hiding place of the Second Foundation.

How did Brother Day die?

After Demerzel's death, Brother Day attacks Brother Dusk in revenge. Of course, Brother Dusk heals - but he retaliates.

Confirming that Brother Day had his Imperial nanites (the tech that allows the Cleons to heal) removed, Dusk shoots him dead.

Dusk orders the palace staff to clear Day's body and the two extra thrones away, cementing himself as the one and only Emperor and gazing down at the Prime Radiant.

But, after his devastating and murderous actions, has he any Empire left to rule?

What is the clasp?

The clasp is a way for robots to share one mind.

Before her death, Brother Day presents Demerzel with the primitive robot head that he obtained after killing Sunmaster-18, telling her that, on Mycogen, they believe she can stop the darkness - and they've waited a long time for her.

Demerzel, who believed all robots except her to be destroyed, is stunned. Day encourages Demerzel to connect (or clasp) with the robot head, which would free her and override her programming. However, Demerzel cannot make the decision, which would interfere with her directives.

Day attempts to get round her programming by convincing her it's not a choice and that she'd just be showing him how to do it. Before she can complete the clasp however, she senses what Dusk is doing in the clone tanks and her programming pulls her away.

However, the end of the episode reveals that there is life in the robot head and, after Day started to prepare it for the clasp, it was able to initiate the clasp on its own, transmitting to robots across the universe.

The clasp is received, Kalle and a non-humanoid robot on the other end declaring that "all the pieces are in place" for them to enter the fray.

What is Earth's role going to be?

Before the episode ends, though, it's time for one more reveal - those robots appear to be on our moon. And, in the final shot of the episode, we see the Earth.

In Asimov's series, Earth is a radioactive and forgotten world, rediscovered by characters later on in the books, as they find out the reasons for humanity's exodus to the stars.

Foundation seasons 1-3 are now available to stream on Apple TV+.

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