Simultaneously, she becomes involved with a New Crobuzonian spy named Silas Fennec, who reveals that the grindylow of the Cold Claw Sea are planning war on New Crobuzon.

Knowing that she must get a message home, Bellis destroys a large part of the Appendix which shows the equations and methods to raise the avanc.

The Lovers find Aum and the information they need, while Bellis uses their time on the island, away from Armada, to get a message home warning of the impending grindylow invasion.

The Lovers' true plan is finally revealed: to use the great speed and pulling power of the avanc to find the fabled Scar, a place in the world where reality breaks down and anything is possible.

They pick up a shipwrecked friend from a different train of possibilities, chances and choices, who warns them of The Scar and that he saw the city fall into the wound of the world and everybody was killed.

Mutiny follows and the people of Armada finally force the city to turn around and head back to the Swollen Ocean, the life of quiet and piracy, that they all want.

He concludes that "The Scar eventually demonstrates enough invention and brutal energy, firmly ruled by a calm architectonic intelligence, to show that Miéville is one of the most imaginative young writers around in any kind of fiction.