The famed Grand Mosque of Agadez, the world’s tallest adobe structure, floated above the desert’s dawn dust cloud like a mirage. William had read many a story about water mirages in the desert, but a mosque mirage? That was something new.

But as much as it looked like a mirage, it wasn’t. There it was, unmistakably, exactly where it should have been, precisely as he had read his compass. He felt an unaccustomed soar of triumph. So much had gone wrong on this trip, in his life, that he’d come to expect bad things, bad endings. But not this time.

He’d live. Janet would live. They’d live to fight and struggle another day.

This outing in the desert, the dumb shortcut, the ill-equipped truck, the ridiculous pressure to save a few hours getting to Agadez and the sheer bad luck of blowing out two tires simultaneously—all those elements of incipient tragedy were now history. This journey would have a happy ending. At least those were his first thoughts as he hurried his pace toward the storied city in the midst of the Sahara Desert.

In the gray light of early morning, houses were appearing now, small tan adobe homes with mud walls and flat roofs and clean-swept yards in front of heavily barred doors. Windows too were barred. Insecurity appeared to have overtaken the small city that had somehow managed to survive for centuries in one of the harshest and most remote locations in the world. Narrow, twisting dirt lanes lined with more houses curved off to the right and left. The city was a jumble, a maze.

“It’s a dangerous place,” a U.S. embassy factotum in the capital Niamey had warned William and Janet just before they set out. He was the only man they had seen in Niger wearing a coat and tie in the 120-degree summer heat. He continued, “There are guerrillas and drugs and lawless soldiers and Italian Cosa Nostra and Nigerian Mafia and al-Qaeda and ISIS and smugglers and cartels and illegal immigrants and so many armies and militias you can’t keep count of them. This place may have been isolated in the past, but now it is the center of everything—everything bad. It is a vortex.” He ended, “Don’t go there.”

“We’ve been to a lot of dangerous places,” William replied. “We’ll think about your warning, but a little risk may not deter us.”

“We’re going,” Janet interrupted her husband in a voice that left no doubt who was the decisive one in this couple. “You government guys are always too cautious. I guess that’s what comes of working for government.” She filled the bowl of her voice with scorn as bitter as vinegar, as thick as gruel.

They took precautions. He hated shaving anyway and avoided it on their travels. His beard had become what a friend would call luxuriant, while a critic might describe it as wild and untamed. In a café a guy had joking called him Osama. They were both partial to Africa-style dress, vivid loose skirts for her and bright untucked shirts for him.

Looking at both of their reflections in the mirror, he joked, “We fit in. We look like a couple of Africans.”

They set out early in the morning on the highway to Agadez. They drove north on the good paved road. A couple of hours later they turned off the highway on what they had been assured was a rough but otherwise easy shortcut. It would get them to the desert capital before dark if they hurried.

So much for shortcuts.

As William hobbled into Agadez in the faint light before sunrise, he did not see a single man, woman or child. The cool of early morning was the most active time in the desert, for animals and humans alike. Where was everybody? Where were the children who always played in the streets? There were so many small children in every African town, and nowhere for them to play except the streets. Nor were there any vehicles. The road, the only real road, was empty. Something had happened, was happening here to make a town of 100,000 people go silent and dead. As dead as the desert that surrounded it. After his momentary sense of relief, and even ecstasy, he started to worry again.

Then one lone vehicle appeared in the distance, light gray like the desert, and traveling fast. It was an open vehicle, a kind of military jeep, with several people inside. Four. They carried rifles. They wore the white robes and turbans of Niger’s desert nomads, the Tuaregs, most of whom were peaceful herders of goats and camels who migrated between desert oases. Relief sprang anew. He was saved.

He waved and walked toward them as fast as his sore feet and aching legs and short breath would allow. God, he was starting to feel old. But now it would be better. He would get them to find his wife. Then he could sleep for the first time in two days.

The Tuaregs pulled up beside him in a cloud of dust. The middle-aged leader said something to the three young men. They unslung their rifles, pointed them at William and gestured for him to lie on the ground. He needed only a couple of seconds to decide to comply.

He talked to them in French, one of the national languages, and the leader understood. He was dressed crisply in spotless white, his eyeglasses—an extraordinary accoutrement in this country virtually without optometrists—lending him a certain air of dispassionate wisdom.

William told him his story: a tourist whose truck broke down in the desert and who had been walking along a camel path for two days. He needed help, for himself, but also for his wife who headed off by herself in a different desert and might be dying, lost and alone, somewhere in the Sahara.

The leader introduced himself as “Colonel Mamadou,” no first name; he clearly was not presenting himself as a friend or peer to this forlorn tourist. He had the air of a kind of desert soldier, a throwback to the proud Tuaregs who ruled the vast north African desert, who fought for decades against the French and British, who stood off the Arabs from Libya and Algeria for centuries.

A Tuareg grabbed each of William’s arms and hustled him into the back of the jeep. They kept their guns pointed at him. A few minutes later they arrived at a long adobe structure surrounded by a wire fence with a dozen cars and trucks parked in front. It was the only three-story building in sight, a long adobe structure surrounded by a wire fence with a dozen cars and trucks parked in front. It looked exactly like what it was: an army post in the middle of Agadez.

Colonel Mamadou dismissed his men and took William into a room, handcuffed him to a chair and left him alone.

A few minutes later a giant of a man, tall and elegant, wearing slacks and a sport shirt, walked in.

“What am I doing here?” William blurted out.

“That’s exactly what I want to ask you,“ the man replied in English.

“Who are you?”

“I am General Hassan.”

Are you with the Tuareg rebels or are you with the army?”

Hassan stared at him silently before saying in a voice of frigid calmness, “I’ll do the asking if you don’t mind. I have only a few questions.” He paused before adding in a voice that was, if possible, even quieter and more frigid, “You will answer.”

The interrogation began.