Season 1 In "
The Emperor's Peace", Hari Seldon's predictions of the Galactic Empire's imminent fall, based on his science of
psychohistory, are dismissed by Brothers Day, Dawn and Dusk, the trio of Emperor Cleon I clones who rule the Empire. Seldon is spared execution for treason after a devastating terrorist attack—the destruction of the
Star Bridge, Trantor's
space elevator—illustrates for Day that there is indeed decay within the Empire. Seldon and his followers are exiled to Terminus to establish the "Foundation", a repository of human knowledge that Seldon claims will shorten the dark age after the Empire's demise from thirty thousand years to a single millennium. In "
Preparing to Live", the Empire investigates the Star Bridge attack but is unable to identify its mastermind, or conclusively attribute it to Seldon or the governments of
Anacreon or
Thespis. Despite Dusk urging that the detained delegations from the two kingdoms should be granted clemency, Day opts for a public execution of all delegates except the two ambassadors, simultaneous with orbital bombardments of their homeworlds. In "
Barbarians at the Gate", a charismatic religious leader, Zephyr
Halima Ifa, revives an orthodox, pre-Imperial dogma that asserts clones do not possess souls. This religious issue and a violent insurrection in the lower levels of Trantor fulfill two key portents of the Empire's decline that Seldon related at his trial. Day grows frustrated with Dusk, feeling his elder seeded these problems decades ago by acting impulsively and refusing to heed Seldon's warnings. While Day departs Trantor to intervene with Ifa, Dusk sends a fleet to visit the Foundation, which has fallen silent. In "
Death and the Maiden", Day attempts to undermine Ifa on the holy moon at the center of the Luminist faith, but she gains the upper hand with a galvanizing speech that subtly criticizes Imperial cloning. On Trantor, Dawn pursues a romance with
Azura Odili, a palace gardener, and bares his deepest secret: he inexplicably has minor genetic traits, such as color blindness, that differentiate him from all previous Cleon clones. Day is agitated by his inability to rein in the defiant Ifa in "
Mysteries and Martyrs", but decides he can upstage her by undertaking Luminism's most sacred pilgrimage. Azura asks Dawn, who lives in constant fear of being replaced by another clone should his uniqueness be exposed, to consider running away with her. In "
The Missing Piece", Day completes the Spiral, a torturous trek to a desert cave pool, and claims to have received a vision of a sacred flower. The Zephyrs interpret Day's vision as a divine pronouncement that he has a soul, rendering any further criticism of Imperial cloning by a Luminist to be sacrilege, and nullifying any threat from Ifa. Day seals his victory by commanding Demerzel, his devoutly Luminist robot majordomo, to covertly assassinate Ifa. Day reflects on his experience in the cave, revealing he had no vision at all. Dawn realizes Dusk knows his secret and escapes the palace in "
The First Crisis". He discovers that Azura is part of a rebel conspiracy which plans to replace him with a compliant duplicate. Dusk arrives with Imperial troops who dispatch the conspirators and their counterfeit Cleon. In "
The Leap", Day tells Azura he has killed all of her relatives and everyone she has ever met, and that she will be shrouded for the rest of her life. Day decides to spare Dawn over Dusk's objections, but Demerzel sees the danger Dawn poses to the dynasty and kills him anyway, affirming that her loyalty to the Cleon dynasty supersedes Day's wishes. Day learns that the anti-Empire conspiracy has tainted the DNA of the entire Cleonic line, affecting all future generations.
Season 2 In the season two premiere "
In Seldon's Shadow", a subsequent Day survives an assassination attempt while he is having sex with Demerzel, and suspects Dawn and Dusk's involvement. Day has decided to halt the degradation of the bloodline by marrying the newly crowned Queen
Sareth of Cloud Dominion, and fathering an heir with her. Wary of Day in the aftermath of the deaths of her entire family, Sareth is not enthusiastic about the proposal. Dawn and Sareth form a connection in "
Where the Stars are Scattered Thinly", and Dusk reconnects with his former lover, Sareth's advisor
Rue Corintha. Dusk offers to show Rue recordings of their encounter, as her memories of the event were wiped per protocol. During a heated argument with Day, Sareth accepts his marriage proposal in "
The Sighted and the Seen". Dusk is disturbed to learn that Day has the authority to conduct memory audits on him and Dawn. Dusk and Dawn's shared distrust of Day grows as they discover that the original Cleon has a much larger memory hoard than subsequent clones, including them. In "
Why the Gods Made Wine", Day introduces his bride-to-be to the people of Trantor, but Sareth upstages him, wins the crowd and leaves Day feeling unsettled. After Demerzel insinuates she was somehow involved in orchestrating the murders of Sareth's family, Sareth confronts Day in "
A Necessary Death". She then proposes to Dawn that he impregnate her instead of Day. Day is unnerved by a Seldon avatar, and orders a blockade around Terminus. In "
Long Ago, Not Far Away", Dusk and Corintha learn Demerzel's backstory. Imprisoned for 5,000 years until rediscovered by young Cleon I, Demerzel spends his lifetime telling him stories of the Robot Wars and grooming him to eventually free her. Cleon finally does in his declining years, but ever wary, he implants a chip in her first that enslaves her to his millennia-long plan to rule the universe. He intends for Demerzel to be his immortal successor, with his clones as the face of the Empire, their development and actions subtly controlled by her. Demerzel confronts the trapped Dusk and Corintha in the season two finale "
Creation Myths". Dusk marks Demerzel's neck with green paint before Demerzel kills him and Corintha. Dawn recognizes the green mark as the sign of a traitor and flees Trantor with Sareth, who is pregnant with his child. Day is enraged by Riose's defiance of his order to destroy more Foundation-allied worlds, and the revelation that the Imperial fleet is in the process of complete destruction via sabotage. Day battles Riose in hand-to-hand combat, and Riose uses a
castling device to switch places with Day via
teleportation, venting the Emperor into space and killing him. On Trantor, Demerzel decants three new Cleon clones, and activates the Prime Radiant.
Season 3 In the third season, 152 years later, Demerzel has been able to use the Prime Radiant to prevent the decline of the Galactic Empire, although it has shrunken while the Foundation has gained more power. Because of this, the Empire was able to hold on to more power than Seldon's original calculations had predicted. By this time, the genetic drift and increasing instability of the Cleon clones has caused the cycle to be shortened. At this point, Dusk is ten days away from ascension and secretly working on a superweapon, Day has abandoned his position in favor of a hedonistic lifestyle, and Dawn is secretly working with Dornick. The arrival of the Mule changes Seldon's psychohistory calculations as events were in motion that predicted the end of the Empire in four months despite their efforts to arrest the decline. Not only that, but the darkness beyond could also represent the extinction of the human species. Dawn went rogue to help Dornick against the Mule when he was unable to gain the support of his brothers and the Galactic Council, but this led to the destruction of the planet Kalgan and much of the Imperial Fleet by the Mule which Dornick admitted was her intention as it would weaken the Empire and strengthen the Foundation, redressing the balance of power that had been upset through Demerzel's use of the Prime Radiant. Dawn was blown into space and believed to have been killed, but he was later rescued and taken captive by the Mule's forces with severe injuries to Dawn's lower limbs. After the Galactic Council went behind his back to make a deal with the Mule, handing over Trantor and Dusk to them, Dusk retaliated by destroying the Council, Cloud Dominion and Maiden with his new superweapon. Day's research into Demerzel's history led him to a cult worshipping another robot head, one that could be used to free Demerzel of Cleon's programming. However, upon his ascension, Dusk launched a coup, destroying all of the Cleon clones and Demerzel, killing Day and rising to power as the sole Emperor as Brother Darkness which he believed to be the true meaning of the prediction about the end of the genetic dynasty and the darkness that came after it. However, Dawn remained alive in custody of the Mule -- revealed to in fact be Bayta Mallow -- while Demerzel had provided the Second Foundation with a safe hiding spot in the Imperial Library that was unknown to Dornick, the Mule and Darkness. Day's efforts to reactivate the robot head resulted in it sending a signal to Kalle and robots that were seemingly based on Earth's Moon. == Literary origins ==