The Long War opens ten years after the events of the first book. Joshua is married to Helen Green, with a family of his own, content to live as a simple homesteader out in the High Meggers, the (differently spelled) neighborhood at least one million Earths removed from Datum Earth. Lobsang is out of Joshua's life, busy running the Black Corporation, which has a monopoly on many important new technologies, including the nonferrous dirigibles that keep all the iterations of Earth in contact, under a loose affiliation known as the Aegis. Joshua's placid life gets a disruptive jolt with the reappearance of Sally Linsay, as prickly and unpredictable as ever. Sally is worried that the trolls kindly, peaceful partners to humans are being slaughtered or maltreated up and down the Long Earth, and she convinces Joshua to try to do something about it, launching him on a new odyssey, with his family along for at least part of the ride.