Her husband is dying, but still she goes to the mountains. She is saving the world she says, though of course, she is not. At best, she is saving the western alpine harvest mouse. At worst, she is wasting her time. She wants to be able to look future generations in the eye, she says, and say she did her part. From his bed, with his delicate veins, her husband says that's right. Either you're part of the solution, he says, or you're precipitate. When he laughs with his eyes closed he doesn't see her start to leave. When she laughs she holds her palms over the paper of his skin.

She goes to the mountains. She goes for days at a time. She gets her mother's texts in batches, at sea level, like spring rain. They explain, with plenty of redundancy, what she already knows: that her husband is dying just this once.

Her mother is wrong though, about the other thing. It's really true. By the time her husband is in the ground, it is entirely possible that the western alpine harvest mouse will be out of time.

She goes to the hospital. She makes sure her husband is looked after. She tells him what she saw. A bird in the distance. A spider in her shoe. They laugh together, and she is gone again. Another week. Another absence.

Her in-laws put it to her in the bluntest way, because this is what in-laws do. Her husband's father says it's only a mouse. You are abandoning my son for the sake of a mouse.

This is in the summer in the depths of a drought. A world of ants crawls in through the windows of her kitchen, seeking moisture. On the phone, with the radio turned low, she watches the little red bodies trekking across fields of newspapers, orange skins, coffee stains.

When she thinks of an answer, it is already Wednesday. She has washed her boots. She has stocked up on food. Ready to go. She thinks that to tell her it is only a mouse is like telling a pole-vaulter it is only the Olympics. I am a field biologist, she thinks. This is my world.

She doesn't tell this to anyone. On Thursday, she leaves.

It is an eight-hour drive to the mountains, and she drives alone. This is fine. She has a spare car battery in her trunk, and a satellite phone in her glove compartment that costs a hundred bucks a minute, or just about, for emergencies. She has day markers in the back seat and flares under the dash, though the flares are long expired and it is possible that she is prepared for a breakdown during the day but not at night. The mountains come into view on the third hour like purple fog, and they turn steadily browner on approach. Her right hand skips through radio stations until she is left with the one where the ads run five minutes each. On either side of the highway, turning black against the sun, she passes signs that say Pray for rain.

The cabin looks out over a valley of grass and rock. In a few months, bright flowers with names like shooting star and Shasta daisy and snow-in-summer will color the view. She thinks of a tufted grass she has named Mary's Misery because the sticky sap gets all over her boots.

For now, there are the white flags marking the entrance to every nest. There is a hawk riding up the cliffs to her right. There is a cloud in the distance that reminds her of rain, though at this time of year, she knows better. She carries in a ten-gallon jug of water from the car, and then groceries.

It is possible that the drought is what she is fighting against. The state wants to build a reservoir in this valley, and it would flood the mice out. So water and her husband are both things she is losing to this fight.

Before falling asleep, she wishes she knew how to describe the western alpine harvest mouse in a way that didn't involve the length of one of its toes, or the precise dimensions of one of its teeth.

She wakes. She works. She loses track of time. The day her supplies run out, she drives back down the mountain into a world of clouds.

They sneak up behind her. They chase her down the road. By the time she makes it to the hospital there is weather all over the radio. The oldies station she has picked for the last few miles pulls its advertisements off the air. There is talk of a storm.

You made it, her husband says.

I'm here, she tells him.

Tell me about the birds, her husband says.

She tells him. And then she talks of other things, and he asks more questions. They exchange sentences the two of them will soon forget. From time to time, someone comments on the changing color of the sky.

They leave the window open so as to be the first to know.

What happens is this: the rains never come. She watches the night lift. Sometime the next day, she loses her husband and then, not much later, her world.

.