Book IV of  Mortal Engines. It’s six months after the tumultuous adventures on Brighton and Wren Natsworthy and her father Tom have taken to the skies in their airship, the Jenny Haniver. Wren is loving life as an aviatrix but Tom is troubled by Hester’s disappearance and the old wound caused by Pennyroyal’s bullet.  Then a fluke encounter with a familiar face sets him thinking about the ruins of London and the possibility of going back. Meanwhile, the fragile truce between the Green Storm and the Traction Cities splinters and hostilities break out again. Events are set on a collision course as things end where they began, with London. Cover art by David Frankland.