The Cloud Roads by Martha Wells

headwinds.
    Stone lifted a brow, deeply amused. “I have great-grandchildren older than you.” He pointed to a white seam on his elbow. “You see this scar? That’s older than you.”
    Moon’s eyes narrowed in annoyance, but he wondered if that was true. He hadn’t been keeping close track, but he knew roughly that it had been around thirty-five turns of the seasonal cycle since his family had been killed. That made him old for some groundling races and young for others. If Stone was really that old, and Moon was really the same species... If this doesn’t work out, you’re going to be spending a lot of time alone.
    He edged over and eased down next to Stone. The blanket looked shabby but it was thick and well made; it didn’t soften the rock but it kept the cold at bay. Rolling on his side, facing away from Moon, Stone said, “I’ll try not to molest you in my sleep.”
    “Bastard,” Moon muttered. He would have retreated to the other end of the cleft in a huff, but Stone seemed to put out almost as much body heat as a groundling as he did in his other form. Still annoyed, Moon fell asleep.
    It was deep into the night and Moon was curled against Stone’s back, when Stone thumped him with an elbow and said it was time to go.
    The mountains stretched on and on, but even when the clouds gathered and they flew through cold mist that was like breathing wet wool, there was no question of getting lost. Moon had always known which way due south was, could feel it as if it pulled at his bones. From the way Stone confidently soared through the thick clouds, never veering from their course, Moon thought he must have a similar ability.
    For the next few days, they flew by day and by night, stopping only briefly to sleep and hunt the sparse game. Moon had seen several different breeds of mountain grasseaters but they were all boney and lean, and didn’t make for satisfying meals. Though the long flights were exhausting, Moon quickly gained stamina. But the part of the day he looked forward to the most was before they slept, when Stone asked him questions about where he had lived, how far he had traveled, what he had seen. With more tact than Moon would have given him credit for, he didn’t mention the Cordans.
    It was strange to talk about the places Moon had been without having to carefully avoid anything that had to do with flying or shifting. In return, Stone talked about flying over the sea realms, seeing the shapes of white coral towers just below the waves, the flickering tails of merrow-people and waterlings as they fled his shadow. It was dangerous to go out over the seas, with nowhere to land if you ran into a storm or grew too tired to go on; it was even more risky to swim in the deeps, where creatures far larger than the biggest land predators lived. Moon had never ventured much past the coastal islands to the south, and found it fascinating to hear what lay further out.
    By twilight on the fifth day, they came to the fringes of the mountains, where the sharp peaks tumbled gradually down into green hills and rocky outcrops were cut through with narrow, rushing streams. This time Stone picked out a grassy ledge wide enough for a fire, though it was warmer down here than on the upper slopes. Moon suspected he just wanted to make tea. When Moon brought back a bundle of deadfall collected from the brush in the ravines, he found Stone shifted to groundling, with a big, woolly grasseater carcass steaming in the cool air and a rock hearth already built.
    After they ate, Moon stretched out on his stomach, basking in the warm firelight, the cool turf soft against his groundling skin, comfortably full of grasseater and tea. From somewhere distant, he heard a roar, edged like a bell and so far away it almost blended with the wind. He slanted a look at Stone to see if they had to worry.
    “Skylings, mountain wind-walkers.” Stone sat by the fire, breaking sticks up into small pieces and absently tossing them into the