I waited on the porch and was relieved when Loyd pulled up before Emelina's household had roused. It was a little odd, living with a family that paid attention to my social life.

Jack stood up to greet me from the back of the pickup and I rubbed his ears. "I brought lunch," I told Loyd, sliding into the cab with a basket Emelina had helped pack the night before.

He smiled wonderfully. "That's mighty white of you."

I didn't know what to make of that. It was something people said, but usually when they said it both people were white.

I asked him to detour past the Post Office so I could check for mail. There was no regular mail delivery in Grace, probably on humanitarian grounds. A daily route up these stairstep streets would have put some postal employee into a cardiac high-risk category. Every family had a box at the P.O., which they could check daily or annually, as they pleased. Emelina leaned toward annual. I persuaded her to turn over the key to me; I was the only member of the household expecting mail.

The mailboxes were built right into the outside wall of the Post Office. I peeked through the little window of the Domingos family drawer and saw the striped margin of an airmail envelope.

"Hallie!" I called to Loyd, waving the envelope as I bounced back to the truck. He didn't seem to register. "My sister Hallie. In Nicaragua." I checked the postmark to make sure this was true, and it was. Mailed nearly three weeks ago. The stamps, two alike, were bright and beautiful, carrying across oceans and continents a child-like revolutionary hopefulness: a painting of a woman picking red coffee beans, and her baby strapped on her back. Hallie was in the fields of her dreams.

I ripped it open and read quickly. She'd arrived mid-September, was fine, got my letters, she spent a few days in Managua and then backtracked straight to the rural area near Chinandega. She'd expected (or feared) a little formality but they put her to work the day she arrived, wearing her one and only dress. "I'm in seventh heaven," she wrote, and I could see her hiking up that dress and striding across the plowed rows, leading a battery of stunned men. "This cotton's been getting sprayed to death and still eaten up with weevils. Cultivation practices are pitiful. I know exactly what to do. I think we'll get productivity up about 100 percent from last year. Can you imagine? You'd think it was Christmas, everybody's already talking about how the collective could use this prosperity: they could get a secondary-school teacher in here full time, or a good adult-ed program."

I got a vivid picture of Hallie's face and could hear her voice as I read. Her hair would be restrained in a red bandana, her face tense with concentration and her eyebrows knit at angles like accent marks. I could also recall her exact expression as she lay on our living-room sofa in Tucson with her long legs propped up, one hand pushing the hair up from her high forehead, while she calmly dispensed information over the Garden Hotline. I understood the full extent to which she'd been wasting her life on house plants.

The letter was short. She was living in a two-room house with a widowed mother of four young children, who insisted that Hallie have one of the rooms to herself-a luxury that made Hallie uncomfortable. There was nothing to spare. The day she moved in, a request went out to the neighbors and somebody brought over a plate and a tin cup for her, and somebody else brought a fork. Both women had recently lost sons.

The territory she would have to cover, giving crop advice, was huge. She was issued a horse. There were problems with the roads, she said, that made Jeeps a less desirable mode of transport for short trips: horses usually weren't heavy enough to trigger the land mines the contras buried in the roads. The horse's name was Sopa del Dia; she was white with gray spots.

She signed it, "Your insane-with-love sister Hallie," with a P.S.:

Re your question about botany: tell your students plants do everything animals do-give birth, grow, travel around (how do you think palm trees got to Hawaii?), have sex, etc. They just do it a lot slower. Bear this in mind: flowers are the sex organs of plants. Tell the boys to consider that when they're buying their dates corsages for the prom.

And a P.P.S.:

Sure I remember when we almost drowned in a flood. Plain as day. God, Codi, don't you? We found those abandoned coyote pups, and the river was flooding, and you wanted to save them. You said we had to. I was chicken because Doc Homer would spank the shit out of us and I wanted to run for it, but you wouldn't let me.

"My sister's saving people's lives in Nicaragua," I told Loyd.

"She's a doctor? I thought she was a farmer."

"People can't live without crops. There's more than one way to skin a revolution."