The bitter winds of winter are howling just outside, but my wife’s hand is warm in mine. In my other hand, I hold a glass of the sweet plum wine this moon is famous for. We raise our glasses, but they meet with a harsh bang instead of the soft clink I expect. It’s enough to jar me free of the dream, and I awake in my cold tent rather than my warm house.

The banging continues intermittently as I crawl out of my sleeping bag and don my coveralls. In the moments it takes me to dress, my two companions outside begin the new day the same way they finished the last one — arguing.

"You’re overreacting," I hear Jack say for the tenth time. "Yes, it’s a little colder than usual this year, but the migration never happens until after the equinox, and that’s still more than a week away."

As I step outside, there’s a final bang as the last upright of Alex’s tent falls, the canvas cover settling slowly atop it.

"The migration has never come this early before," Alex replies, "but that doesn’t mean it never will. We’ve introduced a lot of industry to this moon, and it’s changing things. We’re changing things."

"You mean the weather?" Jack asks. "It’s weather. It’s always changing. I’m not done with the harvest, and I’m not leaving until I am. You do what you want."

I eye the drying lines stretching between the massive trees surrounding our camp. Strung along them are the mushrooms Jack and I have collected over the past several days. Alex has already taken his down and packed them up to hike back down the mountain.

I’m tempted to go with him.

We all know the risk of being caught in the forest during the migration. But the mushrooms are worth a lot of money, and Annie and I need it for the family we’re planning.

Also, it’s hard not to follow Jack’s lead. His great-grandparents were original colonists, and he has more experience with this land than Alex and I combined. He knows a lot, but he thinks he knows everything. And that can be dangerous because, of course, no one does.

As I watch Alex head out, I wonder if I could be making the biggest mistake of my life.

* * *

Despite my misgivings, the day goes well. Jack and I enjoy a bountiful harvest, and the constant motion keeps me from brooding over Alex's absence. Mostly.

We light a fire around dusk, which comes early this deep in the forest, and finish the rest of the plum wine we packed in. I find myself inching closer to the flames as night draws on and the temperature dips again. Just as I’m about to heed the call of my sleeping bag, Jack stands, stretches, and declares he’s in the mood for a walk. There’s a clearing about a mile farther up the mountain that allows for stargazing, an impossibility elsewhere because of the dense canopy.

"You coming?" he asks.

Although I do miss seeing the stars, the chill and my fatigue win out, and I head to bed instead.

* * *

I dream of home again. I sit before another glass of wine, watching ripple-rings disturb its surface. They grow stronger until I can actually feel the tremor that causes them. A moonquake?

The glass tips as the whole house begins to shake, then rolls off the counter and smashes into shards at my feet.

I’m suddenly desperate to find Annie. As I jump up from my chair, her voice reaches me from some distant place. She screams a single word: "Run!"

* * *

I awake thrashing in my sleeping bag, seized by panic and full of adrenaline.

As I hurry into my coveralls, I realize I’ve decided to leave. And not soon, not in the morning — right then. Trying to descend the mountain at night is crazy, but it doesn’t matter because Annie’s voice is still echoing between my ears. Run!

I start to dismantle the tent, then decide to leave it. The same with the mushrooms. I call out Jack’s name, hoping beyond hope that he’s near enough to hear me, but knowing he isn’t. He’ll have reached the clearing by now, and the thousands of thick-trunked trees filling the distance between us will eat up the sound of my voice like a glass of plum wine pitched into a waterfall.

Not that it would matter anyway. I couldn’t convince him to change his mind any more than Alex could. There’s no way he’ll leave, and there’s no way I’m staying, not even to wait for his return.

* * *

I fall repeatedly as I shuffle down the mountain in the dark, tripping over roots that my small torch fails to reveal, but each time I pick myself up and push on. I barely even notice my skinned knees and badly jammed finger.

I trip a final time as the valley comes into view and the sun begins to rise. I don’t go down hard, but the fall frightens me badly — because I shouldn’t have fallen.

I roll over, looking back at the root that snagged me. It protrudes from the ground several inches higher than it did a moment ago.

As I sprint the rest of the way down, and on across the valley after that, an incomprehensible avalanche of sound overtakes me. It’s like a moonquake accompanied by ten thousand peals of thunder that don’t fade.

The trees are on the move.

By the end of the day, the entire forest will have descended, destroying anything and anyone caught in its path. Including my friend.

I curse his stubbornness even as I mourn his loss. Even as I rejoice at the prospect of seeing my wife again.

In the coming days, I’ll warn others about the changes taking place on our new world. I hope they’ll listen.