Just before leaving the cafe, I ran two Google searches. One for my own name. The other for Jeff's. No evidence of anything amiss popped up. Despite his promise to the contrary, Shuman had still not turned me in.

I stood up from the computer and paid the dark-skinned attendant. Then I stepped out again into the Cairo night.

Caesarion's... every feature resembled that of his father, the great Caesar -Cleopatra Georg Ebers (18371898)

Chapter Nineteen.

A niqab has three layers, affording the woman wearing it three options for revealing-or concealing-her face. When all three layers are flipped backward over her skull, the woman's face is completely exposed. The first layer, when pulled down, covers her face but not her eyes. Each subsequent layer affords an additional screen. If all three layers are down, the woman's eyes are shielded completely, but she can still see out. In theory.

I quickly found that, in practice, trying to see through all three layers was like looking through a porthole smeared with black mud. A small porthole. But it was my only choice.

I learned how to wear the niqab the day before yesterday.

I awoke in a seedy downtown hotel room with something tickling my arm. Lazily, I opened my eyes and struggled to adjust them to the light filtering in through a dingy window. Finally, my vision came into focus just inches from an enormous cockroach. I shrieked and quickly sat up, simultaneously flinging my arm. The roach flew across the room and hit a wall before falling to the floor and scampering out beneath the hotel room door. I shuddered.

I shook the last remnants of sleep from my mind and climbed out of the lumpy bed. I flipped a light switch. The light flickered and then came on with a loud hum. Several other roaches scurried out of the room or into darker corners. I've got to get out of this shithole, I thought.

I stared down at the two large, wheeled suitcases I had not bothered opening after returning from the Internet cafe the previous evening. Navigating Cairo with both of them would be impossible, so I consolidated the two bags into one and left a mountain of expensive clothing for the hotel maids. Fifteen minutes later, wheeling one bag behind me, I stepped out of the room and onto the streets of Cairo.

I didn't know any better.

Nearly every passing man who was without an accompanying woman either whistled or shouted something at me on the street. They turned a full one hundred eighty degrees to follow my movement as I passed by in my jeans and T-shirt, my long auburn hair flowing freely behind me. They leaned out of car windows. They honked at me, even more than they honked at each other.

The most common question was "Where you from?" Or simply "American? Australian? English?"

One man, from the driver's seat of a passing taxi, wondered, "Are you Egyptian?" And then declared, "I hope you are Egyptian!"

I imagined some form of international law enforcement posing questions to random passersby on the street. Everyone, but everyone, would have noticed the woman they would be describing.

I stopped walking and looked around. Every person on the street was Egyptian. There were men in khaki slacks and long-sleeved, button-down shirts. The women wore anything from niqab to jeans. Some covered their faces. Others only wrapped their hair in brightly colored scarves. Still others walked with thick dark hair flowing freely. I did not see a single light-haired person. And there were no short sleeves.

I reached up and ran a hand through my long red hair before tying it into a knot behind my head.

I'm probably the only Western woman in all of Cairo walking around by myself right now. And these people, casually going about their business, will form a human trail that leads straight to me.

I need to be invisible.

So at the first opportunity, I purchased the niqab-veil-the accompanying Arab robe called a galabia, a hijab-headscarf-and a pair of gloves. The entire ensemble was pure black.

I was grateful that the woman who sold it to me spoke no English. I had no idea how I would explain such a purchase if asked. She simply wrote a price on a piece of paper, using the numerals I know as arabic. I handed her the money and walked out, my purchase still in the bag.

Now what?

I hailed a taxi.

The only thing I knew logistically about Cleopatra's life was that her ancestors founded the city of Alexandria. Alexandria had been her home. It was the best lead I had.

I could don my new outfit in the Cairo train station restroom-the Ramses station, according to the information desk at the airport-and thus leave town anonymously.

"Where you go?" The cab driver looked at me expectantly.

"I need to go to Ramses Station."

"Oh, Ramses!" the cab driver said enthusiastically.

I climbed into the taxi.

A nauseating twenty minutes later, the taxi pulled into a large square. Traffic converged in three dimensions, with cars coming down from overpasses and up from tunnels to intersect with multiple traffic lanes, but I did not see anything that resembled a train station, or train tracks for that matter.

"No," I said. "Ramses!"

"Na-am!" he insisted, nodding. "Ramses!" He pointed to a large hotel. The Ramses Hilton.

I paid the cab driver and pulled my suitcase from his trunk. Then I stepped inside the hotel and asked how to get to the trains. The Ramses Hilton concierge looked somewhat bewildered and amused as he explained that I was nowhere near the Ramses train station. He offered to hail another taxi for me.

"No!" I said immediately and asked where I could find a Metro.

The concierge pointed across an intersection of ten streets that included an overpass. Still nauseous from the cab ride, I looked wearily across the stormy ocean of cars toward the Metro sign. I looked down at my suitcase and the shopping bag in my hand and sighed.

Feeling shackled to my baggage, I stepped toward the streets. My eyes were drawn to a woman in niqab. With one black-gloved hand, she held a large basket steady on top of her head. Her other arm was looped first through a medium-sized handbag and then through the arm of a small child. Her galabia dragged the ground, and I wondered how well she could actually see through the veil. I would soon find out for myself: not very well.

The woman stepped out into an intersection that was an undulating sea of cars. Yet, the woman and her child appeared protected by some kind of supernatural force field as they walked slowly and nonchalantly between the cars and somehow miraculously reached the other side of the intersection unscathed.

I stepped out into the traffic with my eyes closed.

Somehow, I made it across.

I approached the Metro station the Hilton concierge had indicated. But then I stopped short, fervently scanning my surroundings. I realized that the area I stood in was familiar.

In early 2011, the period that would later be termed the "Arab Spring," this very spot had been the focus of every international headline. I was in Midan Tahrir-Cairo's "Freedom Square"-the gathering place for the thousands upon thousands of Egyptian protestors who would set the stage for the revolutions throughout the Middle East.

At one end of the square was a large red building. I knew from the events of the Arab Spring that within it was the information I needed.

I smiled and stepped confidently toward the Museum of Egyptian Antiquities.

I checked my clunky suitcase at the ticketing building outside of the museum but kept my purse and the shopping bag containing my new clothing. Just inside the museum's entrance was a small gift shop. I purchased a guidebook for the museum and two travel guides for Egypt. I dropped the travel guides into the shopping bag and began flipping through the museum guide as I approached the security line.

The museum was not air-conditioned, and it was packed. It was sweltering inside. Sweaty tourists in shorts and tank tops fanned themselves with brochures while Arabs in long robes flowed like black water around them, apparently unaffected by the heat, many casting disapproving glances at the skimpy Western clothing.

I approached the metal detector. Observing the people passing through it before me, I noticed that they almost invariably set off its alarm. Yet, the security officers waived them through anyway.

When I stepped through the detector, it remained silent. I was unsurprised, with nothing on my person except clothing, books, and my wedding rings. The guard waved me through, and I walked into the museum, searching my guidebook for directions to the Greco-Roman exhibits.

As I turned a corner, something made me glance back at the security guard. He was speaking to another guard. He pointed in my direction. Suddenly cautious, I increased my pace slightly, hoping the change in demeanor would go unnoticed. In my peripheral vision, I could see the guard. He was approaching me. I closed the guidebook and dropped it into my shopping bag.

My eyes began darting around me. There was very little signage either on the exhibits or indicating directions for the museum. The guard was proceeding more quickly in my direction. I thought I saw another behind him, following in his footsteps.

I turned another corner and almost smashed into a large group. Behind me, men were yelling in Arabic. A sea of shiny, straight black hair spread out before me, and I could hear a museum guide chattering in Japanese. Panic began to consume me as I realized just how easily I would be spotted in this crowd.

Desperately, I scanned the room, looking over the heads of the Japanese tour group. I breathed a sigh of relief when I spotted a sign reading "W.C."

I rudely shoved past a few of the Japanese tourists and dashed into the restroom. There were only three stalls and two sinks, but at least twenty women were stuffed into the tiny space. The musk of far too many bodies was heavy, and the restroom itself was filthy. Two women who appeared to be custodial staff sat, immobile, on chairs next to a basket for tips.

Standing nervously in line for a stall, I kept my eyes trained on the entrance to the crowded restroom. The guards did not come bursting in after me. I turned to watch as a young woman adjusted her hijab in front of the mirror. My eyes took in the details of how it was pinned, neatly and decoratively around her skull. I had never before noticed the intricate layering of such a garment. It appeared to be somewhat of an art form.

Shit, I thought. I had not even known to purchase pins for my own hijab. And I had no clue how to affix it.

I approached the woman. "Do you have any more of those?" I asked, pointing to her head. She looked confused, and I pointed again, nearly touching her head, while she looked into the mirror to see the location of my finger. I pulled a fifty pound note from my pocket. Understanding dawned, and the woman reached into her purse. She pulled out a small case full of tiny straight pins and exchanged it for my money.

I returned to my former place in line. While I waited, I looked around at some of the other women in the restroom. I noticed several different styles of wearing the Muslim clothing and felt a bit relieved. If there was freedom in the way the pieces were worn, I could probably pass.

A moment later, I was inside a claustrophobic restroom stall and sweating profusely. It was easily well over a hundred degrees Fahrenheit in a space smaller than an airplane restroom. I pulled the long black galabia out of its bag and over my head, careful to avoid a pool of unidentifiable liquid on the floor. The flowing folds of the garment enveloped my purse, still affixed to one shoulder, and the shopping bag I had slung over the other.

I wrapped the hijab onto my head and pinned it the best I could, struggling to envision the way the woman before the mirror had been wearing hers. Then I added the niqab, all three layers down. Finally, I donned the black gloves. I felt like fainting. I had never been so miserably hot in my entire life.

I emerged from the stall, struggling to adjust to a new standard of vision through the screens over my eyes. I did my best to observe the other women in the restroom. None of them seemed to notice me, or to have registered my transformation. The woman who had sold me her hijab pins was already gone.

I further adjusted my clothing with the benefit of the mirror, until I convinced myself that what I wore could pass for an acceptable form of the Muslim woman's fabric origami. Then I stared at my reflection for a long moment. The bags hanging beneath both of my arms were unrecognizable as such, but they made me appear much chubbier than I actually am. I scrutinized the woman before me in the mirror as objectively as possible. I could find no trace of Katrina Stone.

Three security guards were standing outside of the women's restroom as I emerged within a cluster of niqabis.

"Marhaban," one of the guards said and nodded courteously.

"Ahlan wa sahlan," answered one of the women without looking up. The other women were silent.

The guard said something else to the women in Arabic. His tone and inflection suggested a question. The woman who had initially spoken offered a one word answer, shaking her head gently, and then passed by.

Behind and alongside her emerged a steady stream of women. Some were completely covered. Others wore hijab, but their faces were showing. Still others were completely exposed.

None of them had long auburn hair and blue eyes.

The combination of adrenaline and merciless heat was manifesting as a flu-like alternation between fever and chills. My knees were weak, and I hoped I was not visibly swaying in my step as I passed within mere feet of the three guards waiting for me by the restroom door. I concentrated on holding my breathing steady.

I knew without question that Larry Shuman had turned me in and I was now being hunted. My last known location, the location recorded by my passport and visa at entry, was Cairo. The tunnel vision induced by the niqab seemed to narrow even more as I walked briskly yet casually-I hoped-out of the museum.

A light breeze struck me. It felt like heaven. I habitually reached for my iPhone to check the weather. Then I remembered that both my phone and Jeff's were now in a suitcase that had been sacrificed indefinitely to the Museum of Egyptian Antiquities. I had no earthly possessions except the clothes on my back, the contents of my purse, a few guidebooks, and a dwindling supply of cash.

On the street, I flipped up the top two layers of the niqab in order to pass through several lanes of traffic. That was when I began hearing the word zuro.

The first instance was from a street vendor.

I ducked down an alley and found myself in a small open market selling everything from questionable-looking fish to questionable-looking handbags. At a small stand selling jewelry, I pointed without speaking at a watch that had the correct time and was ticking. The vendor rattled emphatically in Arabic as he pulled down the watch for me to examine. I donned it over a black glove and handed him a few Egyptian pounds. He was still half shouting at me when I walked away, and I wasn't sure if he would follow me and demand more money. But he didn't.

The only word within his rant that I caught, the only word he said more than once, was zuro.

I looked around for a quiet corner devoid of other people. There appeared to be no such thing on the streets of Cairo. I'm going to be spending a lot of time in restrooms, I thought and entered a McDonalds.

Safely inside a stall, the one place I could think of that afforded privacy, I lifted up my galabia and withdrew a guidebook from the shopping bag. In it I found a subway map. God bless, I thought, upon discovering that the Metro connected easily with Ramses Station, which, of course, was nowhere near the Ramses Hilton.

On the way out of the McDonalds, I heard the mysterious word zuro again from a man at one of the tables. On the street, I was sure I heard it again from a passerby mumbling to his friend. And when I bought a subway ticket, I was positive the ticket vendor was referring to me when he said it. So on the subway, I asked.

I was pleased to find Metro cars designated strictly for women, and I wearily sat beside a kind woman who had moved over to offer me room. She explained to me the meaning of the word zuro.

"Do you speak English?" I asked.

At first the woman looked surprised, and she surveyed me up and down in my black Muslim ensemble as if she had just been spoken to by a passing bird. I realized with dismay that this would be the reaction of anyone with whom I tried to communicate in American English. "Little," she said, her accent heavy.

"What is zuro?" I asked. "What does that mean in Arabic?"

"Eh, how to say?" she said, half to herself, and then she said something in Arabic to the woman beside her.

"It is color," the other woman offered, her accent heavy as well. "Blue. Like your eyes." And she pointed through the open slit of my niqab.

So the other two niqab layers came down, their screens like two layers of heavily tinted glass. But even with total physical invisibility, I felt exposed. I was now an Egyptian Muslim with no understanding of the religion, culture, or traditions I should have been taught from birth. And to maintain anonymity, I could not speak. In any language.

The Cairo train station was in shambles. The entire station was under construction-yet business as usual appeared to be taking place.

Stumbling like a drunk, I tripped over construction rubble, the two bags on my shoulders banging awkwardly at my sides like the prodding heels of a rider on a horse. I searched for a ticket window through the veil. Do women actually get used to these? I wondered, fighting the urge to pull back the niqab.

"Alexandria," I said in a muted voice at the ticket window. The ticket seller gave me a strange look and rambled in Arabic for a moment, but I was relieved to see a ticket emerge through the window. I passed him some money. He handed some of it back.

"Alexandria?" I asked of an elderly woman who was clearly not law enforcement. She looked at my ticket and pointed me vaguely to the left, also rambling in Arabic.

"Alexandria?" At the first fork in a road paved with construction rubble, I was waived onto a platform.

"Alexandria?" A woman standing on the platform nodded. I hoped she was right.

Nobody looked at my ticket until the train had been under way for nearly an hour. During that hour, I hoped fervently that I was really headed to Alexandria. Over the course of the two-hour train ride, I read. I devoured the introductory history and the Alexandria-specific portions of my new Egypt guidebooks. And I came to realize I had just made a terrible mistake.

There is virtually nothing left of Cleopatra's Alexandria.

The library itself is gone-I had already known as much. But what I hadn't known was that Cleopatra's palace, her gardens, her army's fleets-everything associated with her reign-had long since gone, literally, into the sea.

It was all under water. And unlike the earthly samples I had obtained from beneath the sea in Naples, this time I had no hope of retrieving what I needed. There was no way I would find any trace of a living plant underwater that had been surviving above ground in her day. I had reached a dead end.

I buried my face in my hands and cried.

I had just failed my daughter.

It is our third night together in Paris.

"I have a daughter," I say. I tell Jeff the story of how my daughter's teenaged fanaticism had been a driving force in my decision to stop working exclusively on anthrax, how it had led me increasingly to cancer research.