Tom and Wren meet Wolf on Harrowbarrow, a burrowing Traction City, which takes them closer to London. With Wolf accompanying them, they fly the "Jenny Haniver" over the Green Storm border, and finally reaching the debris field of London. There they discover that the survivors of MEDUSA have rebuilt a society in London, led by Tom's old boss and now Mayor Chudleigh Pomeroy. Garamond, the paranoid head of security, convinces Pomeroy to keep them there as he suspects that they may inform others of London's survival. Tom, Wren and Wolf eventually discover a new traction town being rebuilt near the ruins, a project that was in-progress long before Magnus Crome decided to use MEDUSA. Noticing that "New London" has no wheels, the leading Engineer Dr. Childermass explains that it uses Magnetic Levitation to float above the ground, making it less harmful to the environment. Wolf slips away from the conversation and escapes back to Harrowbarrow, intent on devouring New London and to use the technology to make his city better.