Babel

After returning from Canton, Robin, Ramy, Victoire, and Letty discover among Professor Lovell's papers that the negotiations in China were never sincere—the British engineered a pretext for war in order to seize Chinese silver. Letty, who had walked in on the group discussing their ties to the Hermes Society, initially pledges to stand with them once she learns the extent of imperial atrocities and the discrimination her friends have faced. The group reaches out to Hermes, whose members favor a political strategy: lobbying Parliament and distributing pamphlets to turn public opinion against the coming war. Griffin, however, has grown convinced that only violence can break the empire's grip, and begins teaching Robin to use firearms. When police raid the Hermes safehouse, Letty betrays the group, and in the chaos she shoots and kills Ramy.

Griffin manages to break Robin and Victoire out of prison but is killed in the process. Stripped of Ramy and Griffin, Robin and Victoire conclude that peaceful reform is no longer possible and resolve to seize Babel's tower itself. They take over the institution, expelling those unwilling to join them and recruiting sympathetic students and faculty. By systematically removing the resonance rods that power Britain's silver-based magic, they throw the country's infrastructure into chaos, demanding peace with China as the price for restoration. Their occupation draws in radicals and reformers who help fortify Oxford against the approaching army, and the disruption escalates until it culminates in the collapse of Westminster Bridge.

Letty comes to the tower to beg Robin and Victoire to surrender, warning that the army will storm the building at dawn. Robin, worn down by grief and guilt since killing his own father in Canton, chooses instead to destroy Babel entirely rather than let it be reclaimed by the empire. Victoire flees into hiding, escaping the tower before the end. Robin and the remaining scholars who stayed with him detonate the tower with themselves inside, annihilating Babel's stores of silver and rendering them useless for further enchantment.

The explosion cripples the silver-powered industrial and imperial infrastructure Britain had built its dominance upon, though the full political aftermath is left uncertain. Robin dies in the tower's destruction, having chosen annihilation of the institution over its continued use as a tool of empire. Victoire survives as the sole main character left alive and free, carrying forward the unresolved question of whether change can come from working within powerful institutions or whether it demands their violent destruction.