Roots: Byzantine court; I, Claudius. Seth is "prince of the dark" and must be "cast down". W.B. Yeats' The Second Coming ("The centre will not hold") John Julius Norwich on Byzantium. The Odyssey (the Dr in the underworld looking for Nyssa) Nyssa's delivery to the 'underworld' of level 14 is reminiscent of funereal rites of the ancient Greeks - a coin below her tongue. The Doctor quotes from Charge of the Light Brigade ("into the valley of death...") Evil eye "If there had to be a Deus ex Machina, it might as well be us"
Fluffs: Shamoor's battle account details alternate between "halosynthegens" and "halosynergens"
Technobabble: Thribarbiturazone is a battlefield hallucinogen.
Dialogue Triumphs: "Why do the shortest journeys seem to take the longest?"
"I'm the Doctor-" "I had a check up last week!"
The Doctor: "I get younger every day, it's alarming"
Shamoor on Sirius: "It has become a mire. No spirit, no heroes, its trade is only in the souls of men"
"An optimist, Tegan? Nyssa would have been having kittens by now"
"The only question left will be who inherits the ruins"
Double Entendres: "You yourself exhibited reduced functioning, erratic heartbeat, lack of flexibility"
"Yes! No! Yes! Yes! No! No! Yes!"
Continuity: Sirius' imperial city is the hub of a great trading empire and located within an asteroid archipelago, featuring golden buildings tunnelled into the rock of the cluster. There are at least 14 civil levels in the city, populated by at least ten human variants as Nyssa sees them. Further colony worlds on Karth and Blousheel are mentioned, as well as a solar station on Jagarnorth. Earth isn't known widely. Power in Sirius is held by its many houses - Varedi hold imperial crests and have done for decades, while the Ejeebi Consortium are off-world and an imperial merchant house. There are slave pits, and those deemed a threat to security are subjected to an amnesiac wipe and delivered to the lowest level of the city, presumably to die.
The wife of the emperor Siris is Anhila, the Imperial consort, queen of poisons, keeper of the dark secrets and queen consort. As part of the women's council, a political group who influences politics via their menfolk, she wrote 'The Trick of Darkness' under the pseudonym 'Hydra.' The book postulated the creation of a common enemy - Seth the renegade, the dark one, prince of demons, as a means of populace control. The book was deemed an outrage, was banned and burned, with only Anhila's copy remaining - she gifted this to the Doctor, and while he always meant to read it, never did.
Robots are literally anathema on Sirius, although the City's defence system incorporates a time-space probability lattice as a defence net, and low level intelligence drones which infiltratesincoming spacecraft (including the TARDIS) to analyse their defences and potential threat.
The Battle of Ragnarok was a battle of Siris' Originals between themselves and led to the foundation of the Empire. Three hundred heroes perished on the plains of Ragnarok, both armies using battlefield halosynthegens. Shamoor was one of the Originals of Siris, the autarch. Shiath was a martial art. Shiarch riddles
The TARDIS' temporal scanner system looks ahead to collect and assess which events might arrive - it looks 25 years either side of Nyssa's logic question. The fast return switch is a switch that needs to be struck, identified in pencil on the TARDIS console. TARDIS' outer shell has an integrity field and is invaded by a mantis-like low-level intelligence drone
Microcircuitry is a specialty of Nyssa's and requires a molecular splicer. Nyssa enjoys the mathematics of probability but to date has only ever explored it theoretically. After the events of Florana (see: Links) she considered leaving the Doctor.
Tegan describes herself as "a fully paid up Aussie republican."
Untelevised Adventures: The Doctor visited the Archipelago "decades ago" - 43 years "as humans measure time, meeting a younger, unscarred Anhila and receiving her gist of 'The Trick of Darkness'.
Location: Asteroid archipelago of Sirius (around Sirius).
The Bottom Line: 'Seth is the demon that every government needs.'
Platt's best adaptation, and, after the mixed result of Cradle of the Snake, a more successful mingling of the writer's world and that of Christopher Bailey. There's a lot of talk in Seth, and a lot going on, but nobody is spared the strong material, with Tegan's seduction scene and Nyssa's time in the Underworld being highlights. Above all, some great casting, with Honor Blackman and David Warner proving an affecting and idiosyncratic royal couple in a cut-throat and uncertain court. Recommended.