Eight months later, I had completed my volunteer stint in Ghana, traveled overland through Burkina Faso and Mali, flown across the continent to Kenya and bused my way to Tanzania, still malaria-free.

My best friend Debbie flew out from Minneapolis to meet me in Tanzania for a month. She brought with her a letter from Simon, telling me that he was seeing someone. He still loved me, he said, but he was sick of waiting with no promises, and she was gentle and attentive and, well, there. What was he to me, anyway? he asked -- a safety net to come home to when the travels were done? He was tired of feeling like the laughing boy in the corner, standing around stupidly while the free-spirited object of his affections danced her way across the globe.

A jolt went through me as I read his letter, but I squelched it. He adored me -- hadn't he told me a thousand times that I was the love of his life? The world's greatest miracle? Wasn't he repeating this message even now, in so many words? Let her comfort him, I told myself. When I get home in a month or two, I'll show her the door.

"Enjoy yourself," I wrote to Simon, "but don't commit. Your girl will return anon."

The following week, waiting in the village of Arusha to arrange a safari, Debbie came down with malaria. We hung out for a week in that strange little town filled with desperate safari hawkers, while she went through the feverish dance I'd come to know so well. By the time she was safely on the plane, and I had set out alone for parts unknown, I was convinced that my body was invincible, a fortress of immunity.

A week later I lay on a lumpy mattress in a barren hotel room in the town of Tanga, Tanzania, lazily watching a fan turn above my head. The air was stupefyingly hot and still. As I stared at the fan's hypnotic spiral, an extraordinary languor seeped into my limbs. My arms and legs felt weighted down, as though an army of Lilliputians had anchored them to the bed. As my mind began to drift toward sleep, a small, reasonable voice in the back of my head made a delicate suggestion: "Before you conk out, why don't you put up your mosquito net?"

My eyes scanned the room vaguely.

"Oh, I don't see any mosquitoes," I told the voice. "Probably the fan's keeping them away. And besides" -- at this point my face undoubtedly wore a faint smirk -- "mosquitoes don't like me."

Three days later I awoke with a hot ache in my bones and the sensation of a thousand tiny needles pricking my flesh. I was in the village of Pangani, on the Tanzanian coast. I'd spent the past two nights camping on the roof of the Pangadeco Hotel with Clemens, an East German medical student with bright green eyes and astonishing black lashes whom I'd met in Tanga.

The Pangadeco was a "find" -- a completely empty hotel less than 100 yards from the beach -- and the previous days had passed in a blissful haze of sun and sand. At night we'd walked for miles into the lukewarm shallows of the ocean, moonlight floating lightly on the water like lace on black velvet. Back on the beach we watched tiny crabs skitter sideways across the sand and drop into their holes, so light on their ballerina claws they left no tracks. The only blot on this idyllic time (besides a nagging anxiety about Simon) was the fact that it was the sacred month of Ramadan, the Muslim holiday in which no one eats between sunrise and sundown, and there was no food to be found during the day except coconuts and under-ripe miniature bananas.

But on this third morning, when I sat up, my head seemed to soar above my body at a great height, as though resting atop an impossibly tall, spindly neck. I stumbled down the stairs to the toilet, awkwardly balancing my unwieldy head, and noticed, with the morbid fascination that accompanies such observations while traveling in "third world" countries, that my shit had turned a bright, almost neon yellow. The beast had entered me at last.

I carted myself to the local hospital for a malaria test, only to find that it was now the end of Ramadan, and the hospital was closed for the festivities. Back at the Pangadeco, the owner telephoned a German doctor who lived in a nearby village. Over a crackly connection, the doctor said I should assume it was malaria and begin treating it right away, rather than waiting to get a test. If it were malaria tropica, the most dangerous strain, and I didn't treat it, I could conceivably die from it, she explained, whereas taking unnecessary medication might screw with my system, but wouldn't kill me. Armed with this advice, I broke out my supply of mefloquine, also known by the brand name Lariam.

Mefloquine was the strongest anti-malarial drug available. Peace Corps volunteers took it weekly, as a prophylaxis, but the doctor in southern France, where I had bought my medications, had advised me to bring along only a small amount, to use as a cure if necessary. Instead, he had given me a combination of more moderate drugs as my weekly preventative medication.

"This mefloquine is too toxic for your body. You should not take it weekly if you will be in Africa for more than two months. This is not just the personal opinion of Dr. Marc Sillard," he had told me sternly, pointing at his chest, "but the strong recommendation of the World Medical Association. I give it to you as a cure only in case of emergency. If you are near a hospital, and can be tested, they may give you something else."

Peace Corps volunteers I met in West Africa reported all sorts of effects from their weekly mefloquine dosage, from depression and mood swings to startlingly vivid dreams and hallucinations. Their weekly dosage was one tablet. The curative dose was three tablets in a single day.

By the time I took my mefloquine, the fevers were in full swing. My body behaved like a furnace gone haywire, my temperature modulating up and up like the ending of a Barry Manilow song until it broke in a dramatic display of sweat and shivers, only to begin the process all over again. I kept a bucket of brown water next to my sleeping bag, wetting a grungy washcloth and placing it masochistically against the hottest spot I could find -- stomach, underarm, inner thigh -- as every hair on my body stood bolt upright on its follicle in protest. Although I was ravenously hungry, when I finally got access to food, I was unable to keep it down. Even with something as innocuous as rice, I would eat one spoonful, and my throat would close on the second bite. Still my mind remained detached, even slightly intrigued.

"Malaria's not so bad," I said to myself.

Little did I know the fun had just begun.

My first mefloquine-altered night was spent in a surreal state, somewhere between painfully acute wakefulness and grotesquely etched, brilliantly colored dreams. Everyone I'd met in my life paraded through my head like a Super 8 movie shot with a hand-held camera. All my loves and betrayals, from early childhood onward, came forward in random order to take their shaky bows -- my seventh-grade best friend who deserted me when I was kicked out of the popular group for gaining weight and "dressing like a Martian"; the mentally disabled boy at my elementary school whom I championed and then betrayed by throwing a single pea in his direction during a cafeteria food fight; the man who whispered "dirty Jew" in my ear on a cross-country bus; the acting teacher whom I worshipped with fervent, unparalleled lust; my dead grandfather; my adoring father and chronically nervous mother; Simon, Simon, Simon, Simon, Simon -- all of them praising and accusing me, grabbing hold of my hands and legs and hair, breaking my heart again as if it were the first time. I shouted their names, sat up again and again, cried and begged forgiveness.

And then, suddenly, I opened my eyes. I had to write a letter to Simon. I shot out of my sleeping bag, slipped under my now-superfluous mosquito net and skidded across the cold cement to my backpack, where I fumbled madly for my notebook and pen. Suddenly there was no time at all, no time to form the words, no time to get the stamp, no time for the letter to cross the ocean and sit in his mailbox. In this moment I understood everything, and he had to understand right now too. I loved him. I needed him. I cherished him. He was my life.

By the time morning came I had no patience left for either malaria or letter-mailing. I had to get back to Tanga, where I could find a reliable phone. I would call Simon and tell him how I felt. Then I'd go to Dar es Salaam and put myself on the first plane home. My journey was over, the endless searching, doubting, questing for self. I knew what mattered. Thank God I'd figured it out in time.

I started to get up to pack my backpack and was stunned to discover that I could not stand and cross the paved roof to reach it. I stood up and sat down again three times in rapid succession, my legs folding beneath me like a marionette's. The dizziness in my head was so severe that palm trees, ocean, clothesline zoomed by me as if on a high-speed carousel.

"What are you doing?" Clemens called out from across the rooftop. "You've been screaming all night long," he added with visible irritation.

"I've got to get to Tanga," I said.

"Are you crazy? You've got malaria. You're not going anywhere."

"But I have to," I told him, my voice rising. "I need a reliable phone line. I have to call."

"Call in a few days," he said. "Look at you. Who do you think you are? Stay in bed for Christ's sake."

"I have to call," I said. "What's the big deal? How much work is it to sit on a bus?"

I started to stand up again, and again I found myself sitting. My head ached like the worst kind of hangover. The colors of the world were too bright. Still I kept trying, over and over, with the perseverance of an athlete training for a race. Never in my life had there been a challenge I'd set my mind to and been unable to achieve, from winning the County Spelling Bee to writing and touring a play to traveling alone through Africa. I wasn't going to be defeated by six feet of cement rooftop.

But I couldn't do it. I rose and fell and rose and fell like a crazy jack-in-the-box before I dived headfirst into the hot morass of my sleeping bag and began to cry like a child throwing a tantrum; heaving, moaning, wailing, shaken by violent sobs that gradually gave way to a bottomless river of fluid grief. I could not stand and walk across the cement. Simon was gone and would never come back to me. Things were fragile. Things could be broken. Things could be lost.

I lay on my sleeping bag, looking up at the pale yellow sky, a 27-year-old white girl from the United States of America, privileged and reckless, sporadically courageous and wildly arrogant, selfish and loving, thoughtless and tender -- sick now, alone now, growing older, growing up.