A Web of Air

Two years ago, Fever Crumb escaped the war-torn city of London in
a travelling theatre. Now she arrives in the extraordinary crater
city of Mayda, where buildings ascend the cliffs on funicular
rails, and a mysterious recluse is building a machine that can fly.
Fever is the engineer he needs - but ruthless enemies will kill
to possess their secrets.

The fabulous sixth book in the Mortal Engines series, from the brilliant
and award-winning Philip Reeve.