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.