destroy the Shield Wall, and warns League Governor Khan of MEDUSA. Khan is skeptical that London will attack, but Fang insists that they should bomb London to destroy the weapon. Convinced that the League will kill innocent people and angry at the idea of destroying his home, Tom storms out and discovers Valentine has infiltrated Batmunkh Gompa as a monk. Tom raises the alarm, but Valentine successfully cripples the League's northern fleet of airships. Valentine duels and kills Fang by stabbing her in the neck, before escaping in his own airship the 13th Floor Elevator. Tom and Hester take the Jenny Haniver and fly it back to London in the hope of stopping Valentine and MEDUSA themselves. With MEDUSA finally launched, Crome begins guiding London east towards the Anti-Traction League's base behind the Shield Wall of Batmunkh Gompa to destroy their defenses and devour all of their settlements. After Valentine returns, Katherine learns that MEDUSA was originally found by Hester's mother, Pandora and that he had killed her to steal it for London. He also admits that Katherine was likely Hester's half-sister. Disillusioned, and horrified by the destructive power of the weapon, Katherine and Bevis conspire to plant a bomb to destroy MEDUSA but are caught in their attempt. The Guild of Historians, led by Tom's boss Chudleigh Pomeroy, come to their aid, and battle with the Engineers. Katherine travels up to the Top Tier to Saint Paul's Cathedral, with Bevis disguised as her captor. Tom and Hester arrive, and Hester attempts to fight her way to Valentine to avenge her parents. Tom is attacked by the 13th Floor Elevator above London and shoots it down. Bevis is killed when the airship crushes him, but Katherine is able to reach Saint Paul's Cathedral. Inside, she sees Hester brought before Valentine. When he attempts to kill her, Katherine jumps in her father's way and is fatally wounded. She falls onto a keyboard, interrupting the firing sequence of MEDUSA, and causing it to malfunction. Valentine and Hester, briefly putting aside their differences, try to take Katherine to Tom to get help, but she dies before they can reach him. Hester leaves with Tom in the airship, while Valentine chooses to stay behind in London. MEDUSA finally misfires, obliterating most of the city and killing Valentine. Hester tries to comfort a grief-stricken Tom as they fly away in the Jenny Haniver, apparently the