The Long Earth

pretty confident that in this case they are discussing us and the airship. And by nightfall, every troll on this continent will be repeating it until they all have it perfect. The songs represent a sort of shared memory – that’s what I believe. There’s even a sort of checksum in the songs, I think, a self-correction mechanism, so that in time all the trolls get the same information reliably. Eventually it will probably go worlds-wide, depending on troll migration patterns. Sooner or later every troll that can be reached will know that we were here today.’
    The others absorbed that in silence. It struck Joshua as an astounding, eerie thought, a song-memory that spanned worlds.
    They walked on. It was a calm, warm afternoon, though marked by brief, light showers that everybody seemed to ignore. There were no vehicles, no pack animals, just a few handcarts, and the fish racks everywhere.
    Joshua said to Sally, ‘Maybe we should cut to the chase. So you know about trolls. In fact you seem very fond of trolls. You know about the humanoid migration. You brought us to this place where there’s a strange human–troll community … You want something from us, that’s obvious. Is it to do with the migration, Sally?’
    She said nothing at first. Then: ‘Yes. All right. I’ve had no intention of concealing anything from you. It’s just that it’s better if you work it out for yourselves. Yes, I’m concerned about the migration. It’s a disturbance that’s echoing up and down the Long Earth. And, yes, I don’t think I can, or should, go investigating the cause alone. But somebody has to, right?’
    ‘Then we have the same goals,’ Lobsang said.
    Joshua pressed, ‘Come on, out with it, Sally. Time for an honest trade. We’ll help you but you need to be fully truthful with us. You knew this place was here, and how to find it. How come? And how did you get out so far in the first place?’
    Sally looked wary. ‘Can I trust you two? I mean
really
trust you?’
    ‘Yes,’ said Joshua.
    ‘No,’ said Lobsang. ‘Anything you tell me that can be used for the betterment of mankind as a whole will be utilized as I see fit. However, I will not do anything to harm you, or your family. Trust me on that. You know something we don’t about the connectivity of the Long Earth, don’t you?’
    A couple walked by, hand in hand; she looked Swedish, he was very nearly midnight black.
    Sally took a deep breath. ‘My family calls them soft places.’
    Joshua asked, ‘Soft places?’
    ‘Short cuts. They’re usually, but not always, far inland, at the heart of a continent. They are usually near water and they get stronger around twilight. Can’t exactly tell you what they
look
like, or how I find them. It’s more of a feeling than anything else.’
    ‘I don’t think I understand—’
    ‘They are places that allow you fast travel over multiple Earths at a time.’
    ‘Seven-league boots—’
    Lobsang murmured, ‘I suspect wormholes would be a better metaphor.’
    ‘But they shift,’ Sally said. ‘They open and close. You have to find the way, and follow it … You have to be taught what to look for. But it isn’t something you learn, it’s like something you remember – something you were told about a long time ago and then when you need it, it pops up. It’s not like Stepper stuttering. It’s more like, well, a helping hand. It’s kind of organic, you know? Like sailors knowing the currents of the sea, the ebb and flow, wind and tide, even the saltiness of the water. And they do drift, they open and close, or reconnect to somewhere new. It’s hit and miss at first, but these days I can get to any destination in three or four steps, if the tide’s flowing right.’
    Joshua tried to imagine this. He visualized the Long Earth as a tube of worlds, a hosepipe, along which he plodded one world at a time. These soft places were like – what? Holes in the pipe walls, enabling you to short-cut vast strings of possible Earths? Or maybe it was like a metro network, invisible beneath a city’s roads, connecting point to point, a network with its own topology independent of what went on above ground. And in that network there would be nodes, exchanges …
    Lobsang asked bluntly, ‘How do they work? Your soft places.’
    ‘Well, how would I know? My father had hypotheses, about the structure of the Long Earth. He spoke about solenoids. Chaotic mathematical structures. Don’t ask me. If I ever find