Editor’s note: The below recap contains spoilers for the Foundation Season 3 finale.

And with that, Foundation Season 3 ends not with a whimper, but with a monumental bang. I don’t think a finale this ruthlessly gamechanging was on anyone’s bingo card. Hopefully, we won’t have to wait too long until Season 4 graces our screens. Until then, “The Darkness,” written by Jane Espenson and series co-creator David S. Goyer, and directed once again by Roxann Dawson, lives up to its title by plunging Foundation into its bleakest timeline yet.

Dusk Destroys the Genetic Dynasty in the ‘Foundation’ Season 3 Finale

Hours away from death, Dusk (Terrence Mann), the destroyer of worlds, enters the chamber where the Cleon exponents are housed. He sneers at the baby as it floats unconscious in its tank, waiting to be decanted and declared the newest Brother Dawn, before returning to his room and letting his attendants dress his naked body in the black and gold robes that signify his transition into Brother Darkness. All affected politeness, Dusk convinces his chaperone, Zagreus (Ahir Shah), to let him walk to his next stop — the medical bay, where the doctors will remove his healing nanite implants — unaccompanied.

Of course, Dusk strides straight back to the exponent room. He triggers a small device three times, and one by one, the tanks housing Dawn, Day, and Dusk’s fully grown back-ups explode, spilling glass, fluid, blood, and decimated limbs onto the floor. Giggling and singing nonsense to himself, Dusk finishes the job by destroying the storage compartment above his head — the one lined wall-to-wall and top to bottom with exponents that will never draw breath. Viscera spills down from above, and Dusk sighs in relief before decanting the baby.

Dusk Murders Demerzel and Day in the ‘Foundation’ Season 3 Finale

Meanwhile, Day (Lee Pace) sneaks through the palace, clutching the concealed Brazen Head close. He finds Demerzel in her room and kneels. Surprised by his return and his gentle reverence, Demerzel welcomes him home with a brief yet meaningful embrace. When Day hands her the Brazen Head, telling her how the Inheritance has mythologized her past life, Demerzel — stunned, trembling, and tearful — cradles the skull like it’s a precious gift. She confirms Day’s suspicion that forming a clasp with another living robot would “overwrite Cleon I’s programming,” but her Imperial directive forbids her from making that choice.

Day offers a middle ground: since she can’t confirm whether this ancient robot skull is alive or dead, she needn’t decide just yet. Instead, Demerzel consents to silently showing Day how one checks for artificial sentient life. The skull sparks with electrical waves at the same moment Demerzel senses someone interfering with the cloning chamber. She sweeps away, leaving Day to guesswork his way through finishing the process. Ambassador Quent (Cherry Jones), surrounded by blaring sirens and panicked bodies, catches Demerzel long enough to ask why the palace is figuratively — and half-literally — collapsing around their ears. Without missing a step, Demerzel tells Quent to retrieve a “triangular book” from her quarters and take it to Trantor’s library. “[Seldon] would tell you it is the best path to the future,” she advises.

Day joins Demerzel in the exponent area. Both try to comprehend the grisly massacre in front of them until a baby’s distant cries guide the pair to the ceremonial room where every previous Brother Darkness has ascended. Dusk places the infant Cleon in the middle of the circle and claims Demerzel denied him any other choice save this one. Demerzel asserts the opposite; she’s the only one who’s bound, and Dusk knows it. Day begs Demerzel not to go to her death, but in her words, Dusk “played it perfectly.”

When Dusk activates the disintegration beam, Demerzel flings herself over the baby. Because she’s a robot, it takes her a long time to dissolve. Yet dissolve she does; Demerzel’s and Day’s gazes lock as she melts down to her golden skeleton, but not before one final insult: the beam slices through her and turns the infant Dawn to ash, making Demerzel’s final sacrifice meaningless. All that remains of the tormented robot with a soul is the Prime Radiant she stored inside her chest, and her skull — half-intact and cooling, but the blue light behind one eye socket flickers off.

Dusk departs with the Prime Radiant in hand. Day chases him into the throne room and pins him to the floor, repeatedly punching his elder brother while screaming in hopeless grief. He only ceases his assault when Dusk, spitting up blood, laughs about the fact Day can’t kill him; unlike Day, Dusk’s nanites were never removed. With that, Dusk shoots his younger brother. As he sprawls on the floor next to a collapsed Day, the latter realizes how the former willingly became the catastrophic event that would usher in the Genetic Dynasty’s fall. As long as he survived and claimed his spiteful revenge, the consequences be damned. “And what comes after [the end of the Dynasty]?” Dusk rhetorically asks before answering with one word that defines both Radiant’s predictions and his new title: “Darkness.” Dusk sips from a flask hidden inside his robes and closes his brother’s dead eyes.

Gaal Dornick Attacks the Mule in the ‘Foundation’ Season 3 Finale

As she meditates inside the Vault, Gaal Dornick (Lou Llobell) reflects on her youthful days. Once, she soothed her nerves by counting prime numbers. Now,she’s used her extensive Mentalic training to create a personal mental fortress. Gaal and Han Pritcher (Brandon Bell) share a tender moment before the Vault propels itself up through the atmosphere. As its dimensions merge with the space station orbiting New Terminus, digital Hari Seldon (Jared Harris) distracts waiting guards allowing Gaal’s group to sneak by undetected.

Han splits off to rescue Bayta Mallow (Synnøve Karlsen), who wakes up to flashing red lights and distant alarm noises. Opening medbay door and spotting no guards she tries hauling Dawn (Cassian Bilton) away with her. He insists his wounds are too severe soBayta flees while Dawn suppresses tears alone and helpless. Han’s search pays off when he prevents a trigger-happy soldier from shooting Bayta but they’ve barely reunited before Han doubles over in distress —the Mule (Pilou Asbæk) is nearby.

Gaal’s team advances upon former Mayor Indbur’s (Leo Bill) office assuming Mule has sealed himself inside. After some strategic thinking courtesy of Ebling Mis (Alexander Siddig) they lay explosives and break in through private bathroom connected late Indbur’s office.Ebling Magnifico Giganticus (Tómas Lemarquis) hide behind bathroom privacy wall while rest charge ahead guns blazing.Telling Skirlet (Isla Gie) hide under desk Mule shoots Leyda (Mark Ebulué) but lets everyone else take their shots — which never hit.

Having fooled them with psychic mirage Mule launches physical sneak attack easily disarming opponents.His mental coercion meanwhile fails overpower Gall’s resolve.He tosses her onto desk like rag doll choking her with both hands maniacally joyous they’ve met at long last.Gaal’s thoughts flash between original vision this moment how it compares present mental fortress.She drags Mule inside latter telepathically taunts about how he could conquer planet after planet never fill void wonders “why your parents loved that baby more than you.”Duped into memory near-death Gaal vanishes from Mule’s grip.Once he’s disoriented helpless Gaal slits throat.

The Real Mule Reveals Their Identity in ‘Foundation’ Season 3 Finale

The aftermath Ebling Magnifico emerge hiding Toran Mallow (Cody Fern), groans pain floor Gaal collects herself lingering presence drops knees Han arrives encourages Gaal screaming anguish let happen Bayta follows behind Han cool calm entirely controls been real Mule all along.