“Shut up, Connie!” said Marta. (Pearl studs, one per earlobe.) “My dad would kill me if he thought I knew this stuff.”

“What you do is between you and your dad,” I said. “Or not. Whatever. But what you know is my business. Obviously you don’t need to put everything you know into practice, just like you don’t have to go spraying the fire extinguisher around because you know how to use it. But if your house is already on fire, kiddos, I don’t want you burning down with it just because nobody ever taught you what was what.”

Raymo shook his head slowly and said again, “Busted.” He drew the laugh he wanted.

“You know what, Raymo?” I asked, tapping a pencil thoughtfully against my teeth.

“What?”

“It doesn’t matter a whole lot what the school board thinks.” This dawned on me forcefully as I said it. I understood this power: telling off my boss at the 7-Eleven, for example, two days before I left Tucson. The invulnerability of the transient. “There’s nobody else to teach this course,” I said. “And I only have a one-year contract, which I wasn’t planning on renewing anyway. I’m not even a real teacher. I’ve just got this provisional certification deal. So that’s the way it is. We’re studying the reproductive system of higher mammals. If I’m offending anybody’s religion or moral turpitude here, I apologize, but please take notes anyway because you never know.”

They were completely quiet, but toward the end of the day you really can’t tell what that means. It could be awe or brain death, the symptoms are identical.

“Miss?” It was Barbara, a tall, thin, shy student (ears unpierced), whose posture tried always to atone for her height. She’d latched onto me early in the semester, as if she’d immediately sniffed out my own high-school persona. “You aren’t coming back next year?”

“Nope,” I said. “I’m outta here, just like a senior. Only difference between you and me is I don’t get a diploma.” I gave them an apologetic smile, meant for Barbara especially. “It’s nothing personal. That’s just my modus operandi.”

The kids blinked at this, no doubt wondering if it was a Latin name they needed to write down.

“Your modus operandi is the way you work,” I said. “It’s what you leave behind when you split the scene of a crime.”

At Grace High I taught Biology I, Biology II, two study halls, and I also pinch-hit an algebra class for a fellow teacher who was frequently absent on account of a tricky pregnancy. My favorite class was Biology II, my seniors-Raymo and Marta and Connie Muñoz and Barbara-but on that day I had a mission and didn’t discriminate among souls. I gave everybody the lecture on baby prevention. Barbara, who was in my study hall and also in the algebra class, got to hear it three times, poor child, and I imagine she was the least in need.

It surprised me as much as the kids, this crusade, and I suspected my motives; what did I care if the whole class had twins? More likely I wanted to be sure of a terminal contract. After the last bell rang I erased the blackboard and stood for a minute sharing the quiet with the bones of my Illinois compatriot, Mrs. Josephine Nash. Our day was over. She gave me her silent, wide-jawed smile. Here was a resident of Grace who had never hurt me in childhood, didn’t make me rack my memory for her name (she wore it on her pelvis), had thrown no spitballs at me nor asked for extra credit, and didn’t suggest that I belonged in Paris, France, or a rock ’n’ roll band.

From the back of the room I could hear the frogs clicking against the sides of their terrarium, constant as a clock: up and down, up and down, exposing soft white bellies. This time next year there would not even be fish or frogs in the river; these particular representatives of the animal kingdom were headed for extinction. Whoever taught this class would have to write Carolina Biological Supply and order those stiff preserved frogs that smell of formaldehyde, their little feet splayed like hands and their hearts exposed.

I stood over the terrarium and peered down into it from above, like a god. The fish hung motionless in its small lake. Droplets of condensation were forming on the underside of the glass top. Getting ready to rain in there. I’d grown fond of this miniature world, along with the kids, and had added my own touches: a clump of bright red toadstools that popped up in Emelina’s courtyard, and a resurrection fern from the cliff behind my house. The terrarium was like a time capsule. I think everybody was trying to save little bits of Grace.

I slid the glass to one side, hating to disrupt the ecosystem but needing to feed the fish. The humid smells of mud and moss came up to meet my nose, and I thought of Hallie in the tropics. What would she do about these troubles if she were here? Well, stay, for one thing, whereas I wouldn’t. I had come here with some sense of its being the end of the line, maybe in a positive way, but I found I had no claim on Grace. Seeing it as “home” was a hopeful construction, fake, like the terrarium. I’d deal with Doc Homer insofar as that was possible in one year, and then I’d rejoin Carlo, or think about another research job; I had no specifics in mind. My future was mapped in negatives. Next year I could be anywhere but here.

I’d told Hallie about my bold, ridiculous little deposition on the pH of the river, and a few days later I’d had to follow up with the news of the river’s getting dammed-questions of pH being entirely academic. I felt humiliated. Eventually she wrote back to say: “Think of how we grew up. You can’t live through something like that, and not take risks now. There’s no getting around it.” She was admonishing me, I guess. I should have more loyalty to my hometown. I wasn’t brave; I was still trying to get around it. A good citizen of the nation in love with forgetting. I pelleted the surface of the water with goldfish flakes. In nature there are animals that fight and those that flee; I was a flighty beast. Hallie seemed to think I’d crossed over-she claimed I was the one who’d once wanted to dig in and fight to save the coyote pups. Emelina thought I’d been ringleader in campaigns to save stewing hens. In my years of clear recall there was no such picture. When Hallie and I lived in Tucson, in the time of the refugees, she would stay up all night rubbing the backs of people’s hands and holding their shell-shocked babies. I couldn’t.I would cross my arms over my chest and go to bed. Later, after my second year of med school, I’d been able to address their external wounds but no more than that.

The people of Grace would soon be refugees too, turned out from here like pennies from a pocket. Their history would dissolve as families made their separate ways to Tucson or Phoenix, where there were jobs. I tried to imagine Emelina’s bunch in a tract house, her neighbors all keeping a nervous eye on the color coordination of her flowerbeds. And my wonderfully overconfident high-school kids being swallowed alive by city schools where they’d all learn to walk like Barbara, suffering for their small-town accents and inadequate toughness. It was easy to be tough enough in Grace.

Well, at least they’d know how to use condoms. I could give them that to carry through life. I settled the glass lid back over the terrarium and turned out the lights. I would be long gone before the ruination of Grace; I had a one-year contract. Now I’d made sure of it.

Rita Cardenal called me up on the phone. She hesitated for a second before speaking. “I don’t think your old man has all his tires on the road.”

“It’s possible.” I sat down in my living-room chair and waited for her to go on.

“Did you tell him about me? About dropping out?”

“Rita, no. I wouldn’t do that.”

Silence. She didn’t believe me. To Rita we were both authority figures-but at least she’d called. “My father and I aren’t real close,” I said. “I go up to see him every week, but we don’t exactly talk.” A pregnant teen could surely buy that.