In cholera-stricken Canton, a scholar, Professor Richard Lovell, uses a silver bar to save a boy and spirits him to the English Factory. Testing the boy on a Chinese–English engraving reveals rare sensitivity to silver’s effects. Lovell offers guardianship and an English education; the boy accepts, takes the name Robin Swift, and departs for London, already compromising himself when he mistranslates to turn away a Chinese laborer at the gangplank.

In London, Lovell naturalizes Robin as his ward and begins years of Latin, Greek, and Mandarin training aimed at Oxford. Hints about a “previous boy” and Robin’s resemblance to Lovell raise unspoken questions of paternity. When Robin misses a lesson, Lovell beats him and issues an ultimatum: total devotion or exile. Robin submits and excels. He arrives at Oxford and, lodged on Magpie Lane, quickly bonds with Ramiz Rafi Mirza from Calcutta. Their cohort soon includes Letitia Price and Victoire Desgraves. Tours of Babel—the tower housing the Institute—reveal its departments, warded Grammaticas, and the eighth‑floor workshop, where Professor Jerome Playfair demonstrates how engraved match‑pairs harness what is lost in translation.

After Robin helps thieves vanish with an invisibility bar, he meets their leader: Griffin Lovell, his half‑brother. Griffin, part of the Hermes Society, exposes Lovell’s secret English family and argues that Babel’s silver enriches empire, militaries, and slavers. He recruits Robin to open doors from within, promising nothing but danger. Robin hesitates, but Playfair’s lectures framing translation as imperial magic, Chakravarti’s guarded truths, and Lovell’s casual cruelty—“She was only just a woman”—push him to signal Hermes. He opens Babel on a stormy night; masked operatives slip inside and escape.

Robin holds the door for more thefts and ferries documents while deepening his friendship with Ramy, Letty, and Victoire. He sees Oxford’s privilege and pettiness up close, rejects the shallow gentleman‑commoners, and learns that “translation is betrayal,” a maxim that mirrors his double life. Playfair introduces limits of silver-work, including a catastrophic paradox when “translation” itself is engraved; Anthony Ribben, a postgraduate, explains the grind and economics behind usable match‑pairs. Over time Robin studies Sanskrit with Professor Anand Chakravarti, while Lovell’s etymology reframes language as history. Wards grow deadlier. During a pickup, a trap screams; Robin is grazed by a bullet, feigns innocence when Playfair appears, and stitches himself alone as Griffin vanishes.

Third‑year pressures fracture the cohort. Supervisors channel Ramy and Victoire into projects that erase their priorities; Letty clashes with Victoire over Kreyòl. Chakravarti apprentices Robin in maintenance around Oxford and reveals “resonance rods,” a hidden network that sustains silver-work across Britain and depends on a handful of Sinologists. News arrives that Anthony has disappeared; Babel moves on without mourning, deepening the students’ sense of expendability. Griffin resurfaces injured, brushes off Robin’s warnings, and proposes explosive theft tied to resisting British aims in Afghanistan. Disillusioned by Griffin’s secrecy, Robin quits Hermes.

Exams loom. Cathy O’Nell quietly shares practical research tips; the cohort notices that the prolific Eveline Brooke vanished years ago. All four pass their silver tests—Robin’s 明白/“Understand” bar produces a palpable clarity—then endure a hostile college ball before finding real community at a Babel party. At dawn they discover Eveline’s grave, confirming her death and sharpening suspicions. Soon after, Babel unveils a telegraph; students take shifts. One night new wards ensnare intruders—Ramy and Victoire on a Hermes errand. Robin frees them, is captured, and faces Lovell, who claims Griffin killed Eveline with a “burst” bar and forces Robin to choose. To survive, Robin divulges a Hermes safe room; Lovell spares him and presses an explosive bar into his hand as a warning.

Aboard a clipper hastily bound for Canton, tensions crack. Lovell offers Robin a “fresh start,” but Ramy and Victoire confront him about years of secrecy. Robin admits informing on a safe house; their friendship shatters. In Canton, Robin sees the opium trade’s human cost. Translating for traders before Commissioner Lin Zexu, he privately tells Lin that compromise with Britain is impossible. Lin orders opium destroyed. Furious, Lovell blames Robin and rushes the cohort onto a ship. At sea, Robin challenges Lovell over his mother; Lovell responds with slurs and threats. Robin activates the “burst” bar; Lovell’s chest explodes. The friends hide the body, maintain a contagion ruse, and reach London unnoticed.

In Lovell’s office, Robin finds correspondence proving war against China was premeditated with traders and missionaries; their work in Canton had been pretext. Letty learns of Hermes and struggles with Babel’s complicity; Victoire describes bars for slave shackles and Leblanc’s dehumanizing requests. They return to Oxford to find Hermes, but at a faculty party Playfair probes their cover. Robin baits him with a false meeting and flees with the others—straight into Anthony Ribben, alive. He leads them through hidden tunnels to the Old Library, Hermes’s safehouse, where a clandestine network works to protect languages and resist imperial silver.

Hermes crafts a multifront campaign: sway MPs, seed Fleet Street, and sabotage a Glasgow shipyard, while Griffin argues for seizing Babel itself. Before deployment, police storm the safehouse. Letty has betrayed them; in the chaos she shoots Ramy, killing him, while Victoire burns Hermes contacts. Robin is captured and tortured by Sterling Jones with bespoke match‑pairs; Griffin rescues Robin and Victoire but is shot in a street confrontation and executed by constables. Fleeing, Robin and Victoire reject reform as impossible and decide to take Babel.

They send a beacon from Griffin’s safe room, witness the wrecked Old Library, then infiltrate the tower. In a tense lobby standoff, Playfair brandishes a gun; Victoire shoots him. With Chakravarti’s aid, they lock Babel down, destroy departing scholars’ blood vials, and declare a strike: no silver, no translation, until Britain abandons war on China. When initial orders to reopen are ignored, infrastructure falters. Robin and Victoire dismantle resonance rods, accelerating failures; a mob tries to burn the tower but disperses before its wards and Chakravarti’s Sanskrit bar. Outside, workers led by Abel Goodfellow erect barricades and ally with the scholars, forcing an impasse with the Army.

The government threatens force and offers amnesty; nationwide strikes spread. Robin presses escalation, proposing to let Westminster Bridge’s silver supports expire; a narrow vote authorizes the tactic. Chakravarti condemns the plan and departs. As silver‑rimmed bullets pierce windows, hope dwindles. News arrives that Westminster Bridge has fallen and a civilian has been shot at a barricade, tipping Oxford into open war. Abel urges evacuation. Letty appears under a white flag to demand surrender, warning the Army will storm the tower at dawn and the Empire will accept casualties. She admits she killed Ramy. After she leaves, Robin proposes a final act: trigger a catastrophic chain reaction by engraving “translation” across cascades of bars, destroying Babel to cripple Britain’s silver power.

With dawn coming, the group chooses. Professor Margaret Craft, Meghana, Ibrahim, and Juliana stay; Victoire and Yusuf leave with Abel, carrying a written account Robin entrusts to him. Through the night they stack hundreds of bars to ensure thorough destruction and deny salvage. As troops move early, Robin stands in the lobby and repeats “Fānyì. Translate.” The chain reaction races through the tower; floors split and shelves crash. In the collapse, Robin thinks of translation as listening and of his mother’s face. Babel falls.

In the aftermath, Victoire refuses martyrdom. Carrying Hermes contacts and Griffin’s letter hinting at wider networks, she escapes England and sails to America, committing to a long struggle across many fronts of empire, determined to make the impossible possible.