“We can’t walk that way.”

“No? What about over there?”

“No.”

“Over there?”

“No. Mushkela”—problem.

My guide Hamoudi Enwaje’ al Bedul is offering a lesson in freedom of movement.

We slog north in the vast, dry, white Dead Sea Valley. We walk the shoulder of a busy highway: a road beaded with enormous cargo trucks that tilt under tons of harvested tomatoes. The road: a conveyor belt of tar, built for machines, inhumanly straight, strewn with small, dead birds hit by onrushing windshields.

The bronze dunes of Wadi Araba lie far behind us—their soft sands replaced by hot gravel. Behind us lie the old camel trails that wend through the Transjordan Range, a wall of pink sandstone, its craggyrincons a dusty blue in afternoon shadow. Behind unspool the farm paths worn by Syrian refugees, the pickers of Amman’s table vegetables. And ahead streaks the narrow corridor of asphalt: a truck road, high-speed, noisy, blistering, hostile to non-motorized life forms. Drivers honk when our pack mules, Selwa and Mana’, clop too far into the oily lanes of traffic. Walking the road is a misery. It is hell. Yet I cannot get Hamoudi to abandon it. He refuses to step even ten yards away from the peppery stink of the exhaust.

Why?

“Police,” he says gravely. Mushkela. Problem.

Walking under power lines is illegal in Jordan, Hamoudi explains: There are power lines along the road. (Is this true? Why? He cannot say.) Or it is the mud: The shrinking Dead Sea, shining dully to the west, is ringed by bogs, by quicksand. A no-go zone. Walking next to the Israeli border—visible in the hazy distance—also is prohibited. Though the two nations are at peace, the area remains a security zone. (We have been hearing Israeli de-mining operations along this frontier for days, the distant boom of manmade thunder.)

I am skeptical. Irritated. I suspect Hamoudi simply wants to reach the King Hussein Bridge where we will part ways—where I leave Jordan for the West Bank—as quickly as possible. But I am wrong.

Security officers begin to stop us.

Traffic police. Army patrols in Land Cruisers mounted with .50-caliber machine guns. Even plainclothes secret police, identified by their gleaming white SUVs and precision haircuts. (“You need to get out and walk more,” I say. The agent grabs his gut: “You are right.” ) We don’t belong on the modern road, Hamoudi and I, with our bucktoothed mountain mules. With our cargo saddles stitched from scraps of orange blankets. With our sun-faded shemaghs—filthy head scarves. With our teapot that may be a bomb. We could be infiltrators, smugglers, troublemakers—in short, nomads, who are always suspect. Nearing Amman, the Jordanian capital, police detain and question us six times in one 24-hour period, a record. This is nearly as many security stops as those racked up on the 2,200-mile journey from Africa. The road is our linear prison. We are its walking inmates. A map suddenly comes to mind: a chart of my police stops across the world. A map of freedom of movement. (We are building such an interactive map. It resides in our Map Room.)

But things aren’t so simple. Freedom of movement begins in the mind.

As we leave the wilds behind, I watch Hamoudi become more cautious, more tentative. He is a supple man: a trained archaeological guide, schooled in Jordan’s deep history, and a friend to people of many nations. He is a bluff storyteller, a laugher, a tireless walker, a superb desert survivor, a proud Bedouin. Yet he grows quieter the farther we range from his beautiful home in the mountains of ancient Petra. He is a Bedul: a tiny ethnic minority in still tribal rural Jordan. And the public highway is a safe—that is, neutral—corridor through the territories of the Other: unrelated tribes. The paved road may be my enemy. It is Hamoudi’s ally.

“I know a good place to stay,” he says after a 30-mile day.

By this he means the ragged tent of an acquaintance, a Sayadeen, a man from a Bedouin group friendly with the Bedul. The man collects aluminum cans beside the highway.

We arrive at this tiny speck of friendship in alien lands as dusk falls. The man’s pretty teenage wife, cloaked in black, hawk-nosed, with gleaming white teeth, takes the mules Selwa and Mana’ off to desert pasture. Hamoudi and I collapse onto worn mattresses in the tent. Exhausted, I stare out the door.

A pod of five-star hotels gleams nearby on the shores of the Dead Sea. Perhaps there are people in the rooms looking out plate glass windows, holding glasses of mini-bar wine, peering into the gathering darkness. They are good people, or at least no worse or better than anyone else on this terrible road. If they squint they might see, some 300 yards away, a glint of wavering light in the desert gloom. It comes from inside a small cube, a structure sheathed in tattered plastic, containing five people. If they had binoculars, they might glimpse the teenage Bedouin girl, Fatimah, working over a fire, cooking eggs and tomatoes scavenged from fields. Her elderly husband, Ali Salam, warms the goatskin body of a rababa, a Bedouin fiddle, near the coals. Their baby, his sand-colored skin bumpy with scabies, coughs and coughs in my lap. His name, Barakat, means blessing. Hamoudi clears his throat to sing. The night highway booms between us.