Timewyrm: Genesys

Timewyrm: Genesys was the 22nd episode of Season 28, it was also the first in the Timewyrm arc

Plot
A spacecraft, holding a mysterious cybernetic queen, drifts into Mutter's Spiral. The woman is possessing the crew, but kills them all when they frustrate her. She plans to set up a slave world on Earth, but soon realises the ship is falling apart. As she meets her apparent death, she can only see the irony in this.

In ancient Mesopotamia, Gilgamesh, king of Uruk, is on the hunt. He meets Ishtar, who claims to be a goddess, but lacks the power to leave the crash site of her lifepod. He rejects her call to join him, and she swears revenge.

On the TARDIS, Ace awakens with amnesia, unable to remember even her own name. The Doctor apologises; he was using the telepathic circuits to edit his own memories, clearing out old junk, and accidentally caught her in the field. He is able to restore her memories. However, in doing so, he triggers an apparition of the Fourth Doctor, a message implanted long ago, warning him about a creature called a Timewyrm. He doesn't remember it, but the TARDIS takes over, and takes them to Earth, where they intrude on Gilgamesh and his friend Enkidu, in battle against warriors of the rival city of Kish. As they cause the battle to end, Gilgamesh takes them for gods, and takes them along to spy on Kish. The Doctor notes odd copper patterns on the walls, and realises something isn't right.

Something, indeed, is not right in Kish. Ishtar, after meeting Gilgamesh, met Dumuzi, Kish's priest of the goddess Ishtar, who accepted her offer and took her to take residence in the temple of Ishtar. Meanwhile, the king of Kish, Agga, is feeling trapped by Ishtar; but he won't rebel, because he fears for his city. His daughter, Ninani, has no such qualms, and enlists a priestess of Ishtar, En-Gula, to help her destroy the false goddess. The Doctor confronts Ishtar, and is captured; he learns that she controls her servants by means of implants that let her overtake their minds and bodies. Ace rescues him before he can be implanted, but her use of Nitro-9 explosives tips Ishtar off to the otherworldly nature of the intruders. She orders Agga to hasten completion of the patterns on the walls; they will constitute a radio transmitter that will let her spread her influence across the entire world. As well, she has a cobalt bomb tied to her biosignature, which will detonate and devastate the planet if she dies. She reveals that she used such a device to destroy her home planet, Anu.

The Doctor, Gilgamesh, and the others escape back to Uruk, bringing with them En-Gula and a musician named Avram. En route, they view Ishtar’s crashed pod, and Avram reveals that he has seen something like it before, in the mountains a week away. Ace secretly pockets a now-defused thermite bomb that was left as a trap on the pod. In Uruk, Gilgamesh deals with a conspiracy against him, and Avram tells the story of his visit to the mountains, and to a man named Utnapishtim. The Doctor concludes that Utnapishtim is an enemy of Ishtar (or rather, Qataka, her true name) from her own world, and may help them against her. He sends Gilgamesh and Ace on a mission to recruit Utnapishtim, while he and Enkidu and En-Gula plan a return to Kish. Ace is not thrilled; she has been busy fighting off Gilgamesh's constant sexual advances, and doesn't look forward to a week with him on the road.

In the mountains, they find that the Doctor was correct. Utnapishtim is the leader of a spacegoing ark, all that is left of his people—and their power source is failing, due to damage on the ship. Nevertheless, he agrees to help, and takes a pair of smaller craft to get them back to Kish quickly. He has a computer virus which should destroy Ishtar—whom, he reveals, is a cybernetic lifeform, a copy of her original humanoid form. Meanwhile, the Doctor, En-Gula, and Enkidu return to Kish, and recruit Ninani; they are captured by Agga, but released by Ninani, and they advance on the temple. Ace, Utnapishtim, Avram, and Gilgamesh arrive at the same time, as does Agga, and the battle begins. Ishtar smashes the device with the virus, but is infected anyway when she hits Ace with an implant; the device was a decoy, and the real virus has been overlaid on their minds. Knowing the bomb will go off if she dies, the Doctor takes it and Ace back to the TARDIS, and uses the telepathic circuits to dredge up the more-technically-astute Third Doctor's personality. As the Third Doctor, he uses the implant to create a copy of Ishtar in the TARDIS circuits, then links the bomb to it, giving him time to defuse it. She infects the TARDIS, but he ejects the infected components, apparently putting an end to her.

The Doctor uses Ishtar's technology from the temple to repair Utnapishtim's ship, and gives him the cobalt bomb to use as a new power source. He then directs them to an uninhabited world where they can re-establish their civilization. Unfortunately, he can't change history; the future holds more natural unhappiness for their friends in Uruk and Kish.

Back in the TARDIS, they are attacked when they enter the Vortex. Ishtar is not dead after all; she has merged with the ejected TARDIS components and become something terrible: the Timewyrm. She is free to roam time and space. The Doctor sets course after her, vowing to destroy her.

Characters

 * The Seventh Doctor
 * Ace
 * Ishtar (aka Qataka)
 * Gilgamesh
 * Ninani
 * Utnapishtim
 * Agga
 * Avram
 * Belkeli
 * Dumuzi
 * En-Gula
 * Enkidu
 * Ennatum
 * Gudea
 * Lagash
 * Puabi
 * Ta-Nin
 * Urshanabi
 * Fourth Doctor (projection)
 * Third Doctor (persona inhabiting the seventh incarnation)

Foods and beverages

 * Ace drinks beer that tastes not quite unlike pig vomit.
 * Rice and barley are grown using irrigation ditches.

Galaxies

 * The Timewyrm refers to the galaxy containing Earth as Mutter's Spiral.

Species

 * Ace is aware that Time Lords can regenerate.

Songs

 * Ace sings Irish folk songs.

Continuity

 * The Doctor erases the parts of his memory he considers no longer important to make room for new memories. As a result, he hopes he never encounters the Chronovores again (The Time Monster) even though he already had in his last incarnation. (The Quantum Archangel) He later says he never met Hitler (Timewyrm: Exodus) even though he did in his last incarnation, (The Shadow in the Glass) and that he has never been to Alaska (Lurkers at Sunlight's Edge) even though the Fifth Doctor had. (The Land of the Dead)
 * The Fourth Doctor gained knowledge of the Timewyrm when he was in the Matrix; (The Invasion of Time) he left a time-delayed message in the TARDIS for himself.
 * The Doctor claims that the Cloister Bell has not sounded since the events of Logopolis. (Logopolis) However this is not true as it sounded briefly after the TARDIS started to travel to Event One (TV: Castrovalva), during the collapse of a Time Corridor (The Mutant Phase) and when the TARDIS got trapped in a Dalek time corridor. (Resurrection of the Daleks)
 * Enkidu reminds Ace of Nimrod, this in turn leads her to remember the events of Gabriel Chase. (Ghost Light)
 * The Doctor remembers the deaths of Katarina, Sara Kingdom (The Daleks' Master Plan) and Adric. (Earthshock) These memories are painful to the Doctor and he wishes to keep the same fate from happening to Ace.
 * Ace still feels some of the after effects of the Cheetah Virus she became infected with in Survival.
 * The Doctor consoles Enkidu (who believes he is the last of his kind) by telling him that another Neanderthal survives to the 19th century. (Ghost Light)