It is the year 1762, and the cream of British high society is attending a ball at Medenham Abbey. Lord Sandwich is throwing the ball on behalf of the Hellfire Club, but is unaware of all of its political ramifications. Amongst the attendees are the Sieur d’Eon, a French spy of ambiguous gender; and also a stranger whom Sandwich does not recognise but whom d’Eon identifies as an agent of the British Service. Sandwich regards the Hellfire Club as something of a lark, but many of its members now hold important positions in the British government, and the Club has thus attracted the Service’s attention. And now that Cousins Justine and Eliza of Faction Paradox are guests at Medenham Abbey, the Service may be preparing to strike.
The Serviceman joins Cousin Eliza at the gaming tables and challenges her to a game of pontoon with interesting stakes: whoever wins a hand may ask the other player a question which must be answered honestly. As the game progresses, Eliza learns that the Serviceman’s name is Sabbath, though he does not seem to be the same Godfather Sabbath whom Eliza knew in the Eleven-Day Empire. Eliza soon realises that Sabbath is trying to feed her information, perhaps to find out how much she already knows -- which isn’t much. He forfeits the match when asked who his employer is, and leaves, advising Eliza to find out what really happened to the prostitute-witch Mary Culver in the caves beneath the Abbey.
Eliza storms out to the Abbey’s greenhouse, infuriated that the Hellfire Club has been keeping secrets from her. She and Justine came here for sanctuary after the fall of the Empire because the Faction was supposed to have allies in this era, but their timeship materialised in Portsmouth in front of a crowd of drunken sailors expecting an invasion from overseas, and she and Eliza were forced to fight their way out, slaughtering innocents. Sandwich follows Eliza out into the greenhouse, but when she asks him about Mary Culver, he hesitates, and the frustrated Eliza uses her shadow weapon to smash apart the greenhouse. She then storms out into the grounds, where she realises she’s being watched and challenges her stalkers to show themselves. Unfortunately, they are more Servicemen, who interpret Eliza’s actions as an attack and storm the Abbey.
Meanwhile, Sabbath follows the Sieur d’Eon into the cavern beneath the Abbey, where he finally meets Cousin Justine. Justine informs him that she has no interest in British politics, but he warns her that British politics have taken an interest in her; the Service will not risk letting the Order of St Francis form an alliance with the Eleven-Day Empire. The other Servicemen then attack, much to Sabbath’s irritation, but Justine reconfigures the timeship into a new form, and monstrous black tentacles rise up from beneath the ground to slaughter the attacking Servicemen.
Sabbath retreats and reports to his superior, the Earl of Bute. Sabbath was opposed to his sending in unnecessary reinforcements, and now it seems that the Earl has succeeded only in declaring war on the Order of St Francis. In the confusion, however, a Serviceman escapes from the Abbey with a glass shard said to have been used by Mary Culver in the Supplication of the Anakim, a ritual ceremony used to open the supplicant’s body to outside influences. Aware of Faction Paradox’s interest in ritual, Bute orders Sabbath to investigate the supplication ceremony and find out if it has any connection to the deaths at Portsmouth.
In the aftermath of the attack, Justine decides to make her presence in Britain official, and thus visits the British court as an ambassador of a foreign power. However, when King George III meets her, he childishly asks her to demonstrate her fantastical shadow weapons by fighting a duel with one of the mechanical soldiers he’s been given as a gift. The automaton identifies itself as a humble servant of the Munificent Army of Peking, and on the King’s orders, it attacks Justine. Justine defends herself, destroying the automaton -- but the King claims to have many more.
Sandwich then takes Justine, Eliza and d’Eon to meet the real head of his Order, who instructed him to throw the ball which has led to so much trouble. It is Mary Culver, or rather, it’s the spirit that possessed Mary during the supplication ceremony when she cut her own throat with the glass shard. She is one of the more important participants in the War, and she’s here to warn Justine and Eliza that House Lolita’s influence is growing on the Homeworld -- and that Lolita intends to spread her influence throughout the Spiral Politic, starting by using the automata to change history in 1762. To this end, the Great Houses must have an agent at court, influencing the King, and the most likely suspect is Bute. Justine and her allies must break Lolita’s hold over the King, with the help of Mistress Culver -- who claims to be acting “out of compassion.”
In fact, Bute is quite disturbed by recent events. The King’s behaviour is becoming increasingly bizarre, and he seems convinced that his army of Chinese clockwork automata will cause the French to take to their heels once sent into battle. Bute visits Sabbath to discuss developments, only to find that Sabbath himself has been developing into something else. After seeing the entity which rose from beneath the ground at Medenham, Sabbath has decided to perform the supplication ritual upon his own person to see what happens. Unlike Mary, he has not been possessed; his personality remains intact, and is merely being influenced by the force acting through him. Thus, he finds that he now has a duty to the Great Houses that supersedes his commitment to the Service: he must find Cousin Justine and bring her to justice...