1916: the Western Front. Private Percy Blakeney wakes up. He is lying on fresh spring grass. He can hear birdsong and the wind in the leaves in the trees. Where have the mud, blood and blasted landscape of No Man's Land gone? 2015: Madison, Wisconsin. Cop Monica Jansson is exploring the burned-out home of a reclusive - some said mad, others dangerous - scientist when she finds a curious gadget - a box containing some wiring, a three-way switch and a... potato. It is the prototype of an invention that will change the way Mankind views his world forever. And that is an understatement if ever there was one...

A generation after the events of The Long Earth, mankind has spread across the new worlds opened up by Stepping. Where Joshua and Lobsang once pioneered, now fleets of airships link the stepwise Americas with trade and culture. Mankind is shaping the Long Earth - but in turn the Long Earth is shaping mankind... A new 'America', called Valhalla, is emerging more than a million steps from Datum Earth, with core American values restated in the plentiful environment of the Long Earth - and Valhalla is growing restless under the control of the Datum government... Meanwhile the Long Earth is suffused by the song of the trolls, graceful hive-mind humanoids. But the trolls are beginning to react to humanity's thoughtless exploitation... Joshua, now a married man, is summoned by Lobsang to deal with a gathering multiple crisis that threatens to plunge the Long Earth into a war unlike any mankind has waged before.

Die Unendlichkeit ist erst der Anfang … 2040–45: Das Universum der Langen Erde, dieser unendlichen Abfolge paralleler Welten, ist in Aufruhr: Nach einem gewaltigen Vulkanausbruch auf der ursprünglichen, der Datum-Erde, suchen Flüchtlingswellen die Siedlungen auf den neuen Erden heim. Während die erfahrenen Pioniere Joshua und Sally helfen, wo sie können, meldet sich ein lang Verschollener zurück: Sallys Vater Willis Linsay, Erfinder des »Wechslers«, mit dem das Pendeln zwischen den Welten erst möglich wurde. Einst verschwand Willis unter mysteriösen Umständen, jetzt will er seine Tochter mitnehmen auf eine Expedition in die geheimnisvollen Welten des Langen Mars. Allerdings verschweigt er Sally die wahren Gründe für diese gefährliche Reise …

It is the middle of the twenty-first century. After the cataclysmic upheavals of Step Day and the Yellowstone eruption, humanity is spreading farther into the Long Earth. Society, on a battered Datum Earth and beyond, continues to evolve. And new challenges emerge. Now an elderly and cantankerous AI, Lobsang is living with Agnes in an exotic, far-distant world. He's determined to lead a normal life in New Springfield—they even adopt a child. But there are rumors, strange sightings in the sky. On this world, something isn't right... Millions of steps away—learning about a hidden family history and the father he never knew—Joshua receives an urgent summons from New Springfield. Lobsang has come to understand that what has blighted his Earth is also a threat to all the worlds of the Long Earth. Countering this threat will require the combined efforts of humankind, machine, and the super-intelligent Next. And some must make the ultimate sacrifice...

2070-71. Nearly six decades after Step Day and in the Long Earth, the new Next post-human society continues to evolve. For Joshua Valienté, now in his late sixties, it is time to take one last solo journey into the High Meggers: an adventure that turns into a disaster. Alone and facing death, his only hope of salvation lies with a group of trolls. But as Joshua confronts his mortality, the Long Earth receives a signal from the stars. A signal that is picked up by radio astronomers but also in more abstract ways – by the trolls and by the Great Traversers. Its message is simple but ts implications are enormous: JOIN US. The super-smart Next realise that the Message contains instructions on how to develop an immense artificial intelligence but to build it they have to seek help from throughout the industrious worlds of mankind. Bit by bit, byte by byte, they assemble a computer the size of a continent – a device that will alter the Long Earth’s place within the cosmos and reveal the ultimate, life-affirming goal of those who sent the Message. Its impact will be felt by and resonate with all – mankind and other species, young and old, communities and individuals – who inhabit the Long Earths…