You know you should tell your partner, but he will want an explanation, will want evidence. The process has been slow, by its very nature, making everyone around you slow, by human nature, to acknowledge it. But you believe it now—though you have no way to prove it.

You need to find someone who will believe you. Given how the phenomenon has developed, you decide to confide in your plants. You trust in the years they’ve spent breathing your breath, hearing your humming as you water them, your senses attuned, the way they always grow toward you now, no matter where the sun is. If anyone, or anything, can give you a sign that you’re not imagining things, it is your plants. The tradescantia, the philodendrons, the spider plants heavy with babies: these are your allies, your first and only defense.

The substance started out fluffy and yellow-green, but has been getting gradually darker. No, it wasn’t just you who thought that; you’ve scoured gardening message boards and found comments from equally baffled green thumbs.

When your partner visits, you test him with a “what if” scenario, and he tries to calm your fears through non-belief, asking for proof, for data. Look at the tests, he says. And yes, when a lab tested the pollen-like substance, they declared it benign.

But you and your plants know better. And your partner only succeeds in increasing your sense of dread by telling you what you know isn’t true, because you’ve seen their spores, you know what’s in season and what’s not, and this dark green powder doesn’t resemble anything you’ve ever seen before.

For weeks now, your indoor plants have been jittery, unfurling new leaves as though arming themselves. This morning when you enter your home office, you see that they’ve turned toward the windows, as though watching for something outside.

When you go for a walk in the afternoon, there’s a charge in the air. Dogs bark from patios and cats hiss from rooftops and trees like they don’t trust the ground. You know it’s in the ground.

This is your sign. Your preparations begin in earnest.

You propagate your army with new cuttings, clipping off spider plant babies and rooting them in egg cartons. In the movies they always show these things as a discrete landing, a sudden invasion from the sky. But while everyone’s looking for danger from above, it’s been sneaking up on them from below. From the soil, from the meandering fungal networks unleashed by the spores that have been falling for months.

Something must have impacted the Earth, fragmented in the atmosphere, come raining down as a dust of imperceptible invaders. It was a threat no one understood because it came cloaked as bounty, as beauty, as juicier tomatoes and plumper corn and sweeter berries. Your neighbors were thrilled with their emerald green grass, their tulips blooming bright on fat stalks, shimmering with life.

Then, one by one, the stories: one neighbor said as soon as they picked the last pear off their tree, thin lines of fungus threaded up it and rotted it to the core. The woman down the street is fretting over her prize rose bushes after watching her phlox molder into furry oblivion as soon as it flowered. You yourself have watched blackberry brambles fall into heaps of must after the berries have been finished off.

No one knows whether the land will support anything else afterward.

Your partner expresses concern when you try to explain, asks if you should talk to someone. But now is not the time for mere talking. Now is not the time for staring helplessly down at the dirt, or up at the sky, cursing whatever brought the hidden scourge. You’ve got work to do, allies to propagate, and your plants seem to know it too. The fattest, healthiest vines present themselves to you like soldiers falling into formation; cuttings anchor themselves with new roots as soon as they’re placed into dirt. Even as you work, you wonder how many of these new lives will be lost in the battle to come.

It’s difficult to tell whether your partner is more upset at the imbalance he thinks is overtaking you, or at you for not “talking to someone” like he keeps telling you to. But last time you talked to someone, he didn’t exactly believe you, did he?

You wonder why he can’t see the signs, but you have no more time to waste. You have an army to cultivate. Whatever you do, you cannot stop your preparations.

It’s time for a test: you take a small potted philodendron outside and hold it near a fern at the edge of your yard. You wait on your haunches, watching. One of the houseplant’s tendrils moves toward the fern, which quivers and moves away. This is no breeze; you move the plant around the fern to be sure. No matter from what angle, the philodendron keeps reaching toward the fern, leaves paddling in its direction. The fern quakes, briefly feinting at your plant before retreating from its grasping tendrils.

And now you see a way forward.

People still don’t want to accept it. After all, this fungus was initially helpful, increasing bounty, augmenting the beauty of the fields. They would rather believe there’s nothing to fear, that this is just a temporary annoyance, that someone will find the right chemicals to bring it back under control. But you know, and your plants know, this substance has other plans.

In your house, dirt churns in pots, spattering onto your desk, the windowsills, the floor. Roots twine and separate, sending up new shoots faster than you can separate them. They multiply until they escape the bounds of their containers, new seedlings tumbling with their soil onto the floor. Roots weave themselves into your area rugs, loosening fibers and wood underneath, taking hold across floors and up walls.

You haven’t seen your partner for several days. Taking some time, he texted. You texted back, saying it was nice of him to tell you, and he’s welcome to come seek refuge when the time arrives.

People always hope for a soft landing. Your plants, however, are doing the work to create one. They will keep growing, engulfing you in safety, shielding the house. They may let your partner in if he comes to you—you will ask them to, anyway.

And he will come. This house will become the center of safety and rejuvenation, burrowing into the fundament, expanding, increasing the radius of vegetal life, the kind that keeps growing, resisting mold and decay. The earth below you will shudder with the tumble of roots and vines, constantly replenishing themselves against the onslaught of grey death. The walls will crumble within the nexus of vines, will flake away in chunks of plaster and brick, flutter away in splinters of wood, but you will still be here, in the center, held safely aloft, swaying above the battle raging underground.

You will hear muffled sirens through your cocoon of leaves. You will hear barking dogs and car alarms, gunshots and screams; you will smell smoke and rot. But you will be safe. And you will hear your partner calling your name, and the plants will decide if they will let him in. You hope they will. But you all have more important things to think about now: growing, renewing, resisting, replacing, replenishing a world rotted to the core.

How much of it will come back—assuming you survive—won’t be entirely up to you. It’s a decision you will share with your new vegetal saviors, the ones who have been with you from the beginning, battling against those who filtered down from the stars.

Only time will tell which side will reseed the world.