Scrivener's moon : the third book in the Fever crumb series

In a land once known as Britain, nomadic tribes are preparing tofight a terrifying enemy - the first-ever traction city. Before Londoncan launch itself, young engineer Fever Crumb must journeyto the wastelands of the North and seek the ancient birthplace ofthe Scriven mutants. The seventh awe-inspiring adventure in the MORTAL ENGINES series.