Cat's Cradle: Witch's Mark

Cat's Cradle: Witch's Mark was the 12th episode of Season 28, it was also was the end of the Cat's Cradle arc.

Plot
The recent damage to the TARDIS has spread, and the time capsule is dying. To live, its link to the Eye of Harmony on Gallifrey must be restored, and to that end, it needs an adaptable organic material that it can mold to its purposes. It takes the Doctor and Ace to 1992 Wales, to the town of Llanfer Ceiriog, where the Doctor has old friends, Hugh and Janet. The local couple takes them in for rest and recovery…but strange happenings are afoot. Local veterinarian Stuart Taylor is called to help deliver a foal, but finds a strange, severed horn—is the horse really a unicorn? An old local called Old Davy is aware of something strange coming, but what? A new community has appeared in London, composed of strange, secretive people with no known identities—and a busload of them have met their deaths in a crash, all dressed the same, all without identification, all carrying briefcases full of money, and some of them bearing strange triangular birthmarks on their necks. Inspector Graham Stevens, the only member of Scotland Yard’s Paranormal Investigations team, is on the case—and the bus’s owner, one Selwyn Hughes, who died in the crash, is a resident of Llanfer Ceiriog…

The Doctor and Ace locate a strange stone circle. It is located in a ruined old village called Dinorben, on land owned by Emrys Hughes, the brother of the deceased Selwyn. Hughes is a surly old man, and threatens them, forcing them to return secretly later…and Ace stumbles through the circle’s gate, dragging the Doctor with her—into another world.

The mystical world of Tír na n-Óg is also dying. It is inhabited by five races—humans, the Firbolg centaurs, the troll-like Fomoir, the hobbit-like (and fox-like) Sidhe, and the Ceffyl, or unicorns. Once its sky carried two suns: the bright, lifegiving yellow of Dagda’s Wheel, and the dim red of Arawn’s Wheel. Now, Dagda’s wheel has vanished, and the land grows cold and inhospitable. Goibhnie, the world’s one-time benefactor, has turned evil, and has unleashed demons to lay waste to the five races. The humans, with their fortress valley of Dinorben enclosing a stone circle, mean to escape through the circle’s gateway to the mythical world of Earth, from whence their forefathers came. In forming this plan, they have abandoned their allies in the other four races, fearing that the presence of the other races on Earth will expose them and bring their doom; and now they find themselves in a standoff with their former allies at the walls of Dinorben. The Doctor and Ace find themselves in this strange world via the stone circle, where they are quickly taken captive. At the decision of the humans’ ruling council, the Tuatha de Danaan, they are sentenced to travel across the land to find Goibhnie and try to restore his sanity as well as Dagda’s Wheel—a mission of certain suicide, but their only option.

Llanfair Ceiriog has other guests as well. An American student, David Gibson, once visited the village in his childhood; now he has returned, with his friend Jack, for a vacation. Tramping around in the woods, David and Jack find something shocking: a centaur, wounded and dying, lying by a stream. Jack goes for the village vet, leaving David behind; he does not find the vet, but instead encounters the village constable, also by the last name of Hughes. Returning to the site, Hughes sets fire to the dying centaur, and drives Jack and David away. Enraged, they attempt to file a report, but are unsuccessful. Meanwhile, Stevens has his own unsuccessful encounter with Constable Hughes; as well, he has had a tip from the vet, Stuart Taylor, about the unicorn—but the vet is missing. Elsewhere, the Doctor and Ace return to Hugh and Janet’s farmhouse, but something is wrong—and in the night, Hugh and Janet find that they are not who they seem at all. Instead, they are monsters, who possess Janet and Hugh.

The Doctor and Ace begin their journey. They first encounter an army of Firbolg, the centaur people, but are allowed to pass when their errand is established. They find a human child with a crippled arm, named Bathsheba, who tells them of the death of her family and the devastation that has come on the land; they take her along with them. They encounter a strange being named Herne in the forest, who seems to know some of the future, and apologizes for things he will soon do to the Doctor. They are captured by a band of Sidhe, but are freed when the Sidhe themselves are attacked. They are again attacked, this time by one of the demons that roam the land; a human chieftain named Chulainn rescues them. Chulainn explains that he is gathering human survivors to go to the safety of Dinorben to join the evacuation. At the Doctor’s request, he agrees to take Ace and Bathsheba with him, and the Doctor slips away to continue the quest. However, Bathsheba follows him, and by the time he discovers her, he is too far away to turn her back. Ace doesn’t take abandonment well, and leaves to go after the Doctor, forcing Chulainn to chase her down. While he is away, the camp is attacked by demons, and everyone is slaughtered, including Chulainn’s wife and unborn child. Grieving, he burns the bodies of the humans, but not those few with a triangular birthmark on their neck; those, he says, are witches, who betrayed the humans. Leaving for Dinorben, they are intercepted by a unicorn named Bat, who forges a telepathic bond with Ace. Chulainn sees only an enemy; but Ace sees an ally, and chooses to leave with Bat. She meets Herne as they travel; he appears to be dying, but his body has a strange effect—it radiates anti-chronons, causing anyone close by to age backward. It was he who attacked the Sidhe camp, allowing them to escape. Ace joins the Ceffyl herd, and they agree to travel back to Dinorben and attempt to escape to Earth, where they will try to obtain help in repelling the demons and restoring Tír na n-Óg. Ace uses her Nitro-9 to blow a hole in Dinorben’s wall, and the unicorns charge the stone circle, aiming for the gateway to Earth.

David and Jack camp in a field for the night, but are awakened by figures in robes, who take David away in a van. Jack runs into the road and is nearly run over; fortunately, it is Inspector Stephens whom he has encountered. After a hurried explanation, Stephens and Jack chase down the van, but lose sight of it long enough for the occupants to escape. They return to the village, and, with no options, call it a night. In the morning, they go in search of clues, and Jack shows him the site where the centaur was burned…and the smell of smoke leads them to a clearing where the robed figures are about to burn David to death. They disperse the group, and free David, who tells them that the figures were going to kill him due to a birthmark on his death—the same mark that the witches in Tír na n-Óg bear, though David does not know it. They confront Constable Hughes, who takes David’s statement, but is no help—but Stephens notices a white robe in the constable’s house. Following more details of David’s story, they visit Emrys Hughes at home; they are all stunned when Ace and the Ceffyl pour out of the nearby stone circle and charge the area. However, they are captured by pursuing soldiers from Dinorben, who begin to cut the horns off the Ceffyl, reducing them to ordinary horses; and Emrys and the soldiers force the humans through the gate to Dinorben. There they are met by the just-arrived Chulainn, who accuses Ace of working with the witches—but at that moment, Ace’s link to Bat is broken as the unicorn’s horn is severed, incapacitating her.

The Doctor and Bathsheba have encountered more Firbolg, led by a charismatic unicorn named Daffyr. Daffyr has an unexpected guest: the human veterinarian, Stuart Taylor. Taylor explains that he had been under some strange influence after finding the unicorn horn; and after contacting Inspector Stephens, he had been compelled to drive his car through the gate at the stone circle, where he was captured at Dinorben. When the spell broke, he was sent out to find Goibhnie—and he ended up here. The Doctor plans to use Taylor’s vehicle to complete the quest—but in the meantime, Daffyr has made an enormous accomplishment: he has slain a dragon, and now there will be a feast. The Doctor determines the dragon is bio-mechanical, living flesh over an artificial frame; he takes its positronic brain. He combines the brain with Taylor’s car radio to create a transmitter, and signals Goibhnie, whom he has begun to suspect is more alien than supernatural. They are attacked by demons, and the car is destroyed; but Goibhnie arrives in a saucerlike aircraft, and rescues Taylor, Bathsheba, and the Doctor, and takes them to his island stronghold. He is revealed to be a long-lived Troifran scientist; he created this world’s populations by genetic engineering, using DNA from humans and other terrestrial creatures combined with a protoplasmic organic material. Herne, incidentally, was a strange and unexpected mutation. It was all intended to be a long-term social experiment; but now it has ended, and the artificial sun he created—Dagda’s Wheel—has exhausted its fuel supply and gone dark. Viewing the inhabitants as just experimental data, he is preparing to depart the world and return home with his results. However, the Doctor reveals that his failed experiments—the demons—have escaped containment and have begun to ravage the land. He is unable to appeal to Goibhnie’s morality; but when he frames it as an opportunity to extend the experiment to long-term, independent results, Goibhnie reconsiders, and agrees to refuel Dagda’s Wheel and recover the demons before leaving. He reactivates the artificial sun, and then takes the Doctor and the others in his aircraft to Dinorben to intercept the demons, which are now assembling en masse—but why are they suddenly doing so?

Ace finds the answer when the sun returns. The Tuatha leader, Dryfid, quickly seizes the opportunity to make peace with the other races and assemble to battle the demons, allowing the races into Dinorben. However, the Tuatha de Danaan military commander, General Nuada, is behaving strangely; and Ace discovers he secretly bears the witch mark. It is he who is coordinating the demons, intending to let them through the gate; and when they have slaughtered all of Dinorben, they will invade Earth, and find new hunting grounds there. He confronts and captures Ace, but is in turn confronted by David and Jack—and to everyone’s shock, including his own, David is revealed to be a demon himself. He was only human once, but as a child, he was possessed and transformed at Llanfair Ceiriog, resulting in the witch mark on his neck. Nuada and David transform into monstrous forms, and go to the gates to let the demons in, dragging Ace and Jack with them.

The Doctor, Taylor, Bathsheba, and Goibhnie arrive, and begin organizing a final plan. The will relocate the stone gateway—the transmat—to the gates, and Goibhnie will reprogram it to terminate at the containment unit near his island; the demons, pushing through, will be transported there. But first there is Nuada to deal with; and Goibhnie and Taylor go to stop him. He mortally wounds Goibhnie, but David, struggling to hold onto himself, transforms fully and kills Nuada. He returns to human form and collapses; the Doctor saves him from the vengeful Tuatha. Goibhnie is dying; but he gives the Doctor the power pack from his breathing unit to reactivate the gateway, then dies. The Doctor does so, but is unable to program it for the containment unit; instead, he redirects it into Dagda’s Wheel, where the demons will burn and provide more fuel for the artificial sun. Soon the battle is over, and Tír na n-Óg has two more millennia to live.

All is nearly over, but not quite. Dryfid adopts the homeless Bathsheba. The Tuatha will destroy the gate, preventing any further temptation to return to Earth; Ace provides them with Nitro-9 for use in destroying it after she and the others depart. However, before they can leave, the dying Herne joins them, and the Doctor determines to save him if he can—after all, only the Doctor can endure the anti-chronons he emits. The Doctor threatens the demonic protoplasm in David with fire, forcing it to escape, where the Doctor collects it; David is now free of his possession. They exit through the gate, which is promptly destroyed. On Earth, they find that some of the unicorns survived; and as their horns were inexpertly removed, they will grow back eventually. The Doctor contacts UNIT to enlist help in ensuring the unicorns’ safety. The Doctor collects Old Davy on the way to the TARDIS, enlisting the man to help carry Herne—but he realizes the two have a connection already. Inside the TARDIS, Old Davy and Herne merge into one; from Herne’s perspective it is death, but from Davy’s it is a new existence. The joined creature vanishes, leaving a mass of the organic protoplasm—and the silver cat manifestation of the TARDIS appears, and begins using the protoplasm to heal the TARDIS’s link to the Eye of Harmony. As the TARDIS is restored, the cat shuts down…but unknown to the Doctor, a speck of protoplasm from one of the demons has contaminated the mixture. There will be consequences.

Characters

 * The Seventh Doctor
 * Ace
 * Lynx
 * Bat
 * Bathsheba
 * Chulainn
 * Daffyr
 * David
 * Dryfid
 * Emrys Hughes
 * Goibhnie
 * Inspector Graham Stevens
 * Herne
 * Hugh
 * Constable Hughes
 * Jack
 * Janet
 * Nuada
 * Old Davy
 * Rhys
 * Selwyn Hughes
 * Stuart Taylor

Books

 * The Book of Rassilon starts with "In the beginning...".

Foods and beverages

 * The Doctor and Ace eat potato and leek soup.
 * The Doctor fries up bacon for everyone.
 * Ace doesn't like Spam.
 * The Doctor claims that there's a fish and chip shop in Rhyl "whose Spam sandwiches can't be equalled this side of the Crab Nebula."

Individuals

 * Ace is not very religious.
 * Lynx, the silver cat which has been popping up, is generated by the TARDIS, and normally resides in a cat's cradle of mathematics in the time rotor when not needed.
 * Stuart Taylor is the local vet.

Organisations

 * Scotland Yard has a one-man Paranormal Investigations Team consisting of Inspector Stevens.

Planets

 * Earth is widely recognised as one of the causal nexus points of the galaxy.

Species

 * A speck of demonic protoplasm infects the TARDIS.

Continuity

 * The clones of the Doctor and Ace would later appear in Return of the Living Dad.
 * The effects of the protoplasm on the Doctor and the TARDIS would continually be shown in later novels up until its expulsion in Deceit.
 * In Transit, Lynx and another cat from the TARDIS almost fight each other, the other cat seemingly representative of the protoplasm.
 * The Doctor once again encounters a biomechanoid dragon, having previously met the "Dragon" of Iceworld. (Dragonfire)
 * The Doctor comments that he recalls a spider almost killing him. (Planet of the Spiders)
 * Gallifrey as a source of "morphologically unstable living organic matter" may refer to validium. (Silver Nemesis) Other sources include Axos, (The Claws of Axos) and possibly Nestene matter. (Spearhead from Space)
 * Block Transfer Computation was discovered by the Logopolitans. (Logopolis)
 * The mention of King Arthur is an indirect reference to Battlefield.
 * The Doctor refers to the time he took his past companion Mel to a Welsh holiday camp in the 1950s, and mentions acquaintance Goronwy. (Delta and the Bannermen)
 * Ace mentions that she used to be waitress (Dragonfire) and remembers the time she met the Cheetah People. (Survival) She also remembers the time she went to 1963. (Remembrance of the Daleks)
 * Ace is reminded of the Haemovores when the demons of Tír na n-Óg are fought off using faith. (The Curse of Fenric)