When Dr. Burrows begins to notice strange 'pallid men' where they live in Highfield, and then promptly goes missing, Will and his friend Chester go search for him.

They avoid the Styx soldiers, who patrol the city with their vicious stalker attack dogs, and eventually emerge on the bank of the Thames.

With the help of Imago Freebone, a member of Uncle Tam's gang, Will and Cal escape to a small hiding place halfway between the Colony and the Eternal City.

There, they rest and mourn for Uncle Tam; and are told by Imago that Chester's train to the Deeps will pass directly under their hiding spot shortly.

The novel was initially self-published under the title The Highfield Mole: The Circle in the Spiral on 17 March 2005, with a limited run of 500 hardbacks and 2,000 softback copies,[1] financed by the sale of Roderick Gordon's house.

Cunningham, while working for Bloomsbury in London, famously signed up J. K. Rowling,[2] and this connection led to the book being branded "the next Harry Potter".

With the announcement of the publication date, and press coverage in the UK, the price of the original self-published books jumped dramatically, with one copy selling for £950.

In Britain, children's author Philip Ardagh, reviewing for The Guardian, thought the long wait for Will to discover the underground city could dull the reader's anticipation, noting that the event did not occur until page 170.

[12] In The Sunday Times of 7 July 2007, Nicolette Jones described the book as "a good adventure yarn ... [b]ut after 460 suspenseful pages it is frustratingly inconclusive."

She noted the book became a best-seller the month of its release based simply on "stories about its discovery by [publisher] Barry Cunningham, who "found" Harry Potter.

The Horn Book Review felt readers "may lose patience with the slow beginning", but observed that adventure lovers would still like the plot.

[17] Reader Jack Davenport garnered critical praise for his "haunting tone" and his ability to depict the people of The Colony with an Irish-sounding accent and their rulers with an "intimidating aristocratic hiss.