A Darkling Plain (Mortal Engines #4) | Philip Reeve

The once-great traction city of London is now just a radioactive wreck, a ruin haunted by electrical discharges and the dashed hopes of the people who once called it home-people like Tom Natsworthy. Twenty years after he fled, intending never to return, he discovers that something stirs in the remains of the old city. Meanwhile the fragile truce between the Green Storm and the Traction Cities splinters and hostility breaks out again. Events are set on a collision course as things end where they began, with London... But even as Tom and Wren hurry to uncover the mystery of London, Hester Shaw-estranged from her husband and her daughter-tracks the resurrected Stalker Fang, who has found another way to end the war and all life on the planet once and for all.