The other truck took a position by the roadside stands.

Kane hopped out and came back to open her door. It could be taken as a chivalrous act in any normal circumstance. At the present time it was merely a precaution. He offered a hand to help her out.

Safia refused, climbing free herself.

Cassandra came around the back of the truck. She carried the silver case. “What now?”

Safia searched around her. Where to begin?

They stood in the middle of a flagstone courtyard, walled and bordered by small orderly gardens. Across the courtyard, a small mosque rose. Its whitewashed minaret climbed blindingly into the midday glare, topped by a brownish gold dome. A small circular balcony at the top marked the place for the muezzin to sing the adhan, the Muslim call to prayer, five times a day.

Safia offered her own prayer. Silence was her only answer, but it still gave her comfort. Within the courtyard, the sounds of the surrounding town were muted, hushed, as if the very air had stilled at the holiness of the shrine. A few worshipers moved discreetly through the grounds, respectful of the burial tomb that stretched along one side: a long, low building, framed in arches, painted white, trimmed in green. Within the building stood the gravesite of Nabi Imran, the father of the Virgin Mary.

Cassandra stepped in front of her. The woman’s impatience, her pent-up energy, stirred the air, leaving a wake behind her that was almost palpable. “So where do we begin?”

“At the beginning,” Safia mumbled, and strode forward. They needed her. Though a prisoner, she would not be rushed. Knowledge was her shield.

Cassandra strode after her.

Safia walked toward the entrance to the burial sanctuary. A robed man, one of the tomb’s attendants, strode out to meet their party.

“Salam alaikum,” he greeted.

“Alaikum as salam,” Safia responded.

“As fa,” he apologized, and pointed to his head. “Women are not allowed into the tomb with their hair uncovered.” He pulled free a pair of green scarves.

“Shuk ran.” Safia thanked him and quickly donned the apparel. Her fingers moved with a skill she long thought lost. She found not a small degree of satisfaction when the man had to help Cassandra.

The caretaker stepped away. “Peace be with you,” he offered as he retreated to the shaded gallery, back to his post.

“We’ll have to take off our shoes and sandals, too,” Safia said, nodding to the row of abandoned footwear outside the door.

Soon barefoot, they entered the tomb.

The sanctuary was simply one long hall, encompassing the length of the building. At one end was a raised brown marble headstone the size of a small altar. Incense burned atop the marble in a pair of matching bronze braziers, giving the room a medicinal scent. But it was the grave below the headstone that captured the immediate attention. Down the middle of the hall stretched a thirty-meter-long sepulcher, raised a half meter above the floor and draped in a rainbow of cloths imprinted with phrases from the Koran. Flanking the grave, the floor was draped with prayer rugs.

“That’s a big grave,” Kane said softly.

A single worshiper rose from his rug, glanced at the newcomers, and silently exited the room. They had the space to themselves.

Safia paced the thirty-meter length of the shrouded tomb. It was said that if you measured the length along one side of the sepulcher, you’d never get the same measurement on the other. She had never tested this bit of folklore.

Cassandra followed at her shoulder, gazing around. “What do you know about this place?”

Safia shrugged as she circled the end of the tomb and began the return journey toward the marble headstone. “The tomb has been revered since the Middle Ages, but all these trappings…” She waved her hand to encompass the vault and courtyard. “All of this is relatively new.”

Safia strode forward to the marble headstone. She placed a hand on its surface. “This was the spot where Reginald Kensington excavated the sandstone statue that hid the iron heart. Some forty years ago.”

Cassandra stepped forward with the small case. She circled the stone altar. The floating snakes of incense from the pair of braziers stirred in her passage, an angry, writhing motion.

Kane spoke up. “So the Virgin Mary’s father is really buried here?”

“There’s some controversy surrounding that claim.”

Cassandra glanced at her. “How so?”

“Most major Christian groups—Catholics, Byzantines, Nestorians, Jacobites—believe Mary’s father was a man named Joachim. But this is contested. The Koran claims she descended from a highly respected family, that of Imran. As does the Jewish faith. According to their stories, Imran and his wife desired a child, but his wife was barren. Imran prayed for a male child, one whom he would dedicate to the temple in Jerusalem. His prayer was answered, his wife became pregnant—but with a female child. Mary. Joyous still, her parents devoted her to live a life of piety in honor of God’s miracle.”

“Until she got knocked up by an angel.”

“Yes, that’s when things get sticky between the religions.”

“What about the statue, the one at the head of the grave?” Cassandra asked, drawing the conversation back to their goal. “Why was it placed here?”

Safia stood before the marble headstone and pondered the same question herself, as she had on the whole journey from London. Why would someone place a clue to Ubar in a place tied to the Virgin Mary, a figure revered by all three religious faiths—Judaism, Christianity, and Islam? Was it because they knew the site would be protected throughout the ages? Each religion had an interest in preserving the tomb. No one could’ve anticipated Reginald Kensington excavating the statue and adding it to his collection back in England.

But who originally brought the statue to the shrine and why? Was it because Salalah marked the beginning of the Incense Road? Was the statue the first signpost, the first trail marker leading into the heart of Arabia?

Safia’s mind spun with various scenarios: the age of the statue, the mysteries surrounding the tomb, the multifaith veneration of the site.

She turned to Cassandra. “I need to see the heart.”

“Why?”

“Because you’re right. The statue must’ve been placed here for a reason.”

Cassandra stared at her for a long moment, then knelt atop one of the prayer rugs, snapped open the case. The iron heart shone dully within its black rubberized cushioning.

Safia joined her and lifted the heart free. Again she was surprised by its weight. It felt too dense for plain iron. As she stood, she felt the vague sloshing from within, heavy, as if some molten lead filled the heart’s iron chambers.

She carried it over to the marble altar. “The statue was said to be propped up here.” As she swung around, a few bits of frankincense dribbled from the end of one of the heart’s vessels and scattered like salt atop the marble altar.

Safia held the heart up to her own chest, positioning it anatomically—ventricles down, the aortic arch passing on the left—as it would lie in her own body. She stood above the long narrow tomb and pictured the museum statue before the explosion had blasted it apart.

It had stood almost seven feet, a draped figure, wearing a headdress and face scarf, typical of the bedouin today. The figure had borne aloft a long funerary incense burner, on the shoulder, as if aiming a rifle.

Safia stared down at the grains of ancient frankincense. Was the same incense once burned here? She cradled the fist of cold iron in the crook of one arm, and picked up a few crystalline grains and tossed them in a neighboring brazier, sending up a prayer for her friends. They sizzled and gave off a fresh whiff of sweetness to the air.

Closing her eyes, she inhaled. The air was redolent with frankincense. The scent of the ancient past. As she breathed, she traveled back in time, to before the birth of Christ.

She pictured the long-dead frankincense tree that produced this incense. A scraggly, scrubby tree with tiny gray-green leaves. She imagined the ancients who harvested the sap. They were a reclusive tribe in the mountains, so isolated and old that their language predated modern Arabian. Only a handful of tribesmen still survived in isolation up in their mountains, eking out a meager living. She heard their language in her head, a singsong sibilance that was compared to birdsong. These people, the Shahra, claimed to be the last surviving descendants of Ubar, tracing their lineage to its founding fathers.

Had such a people harvested this incense themselves?

As she drew the past into her with each breath, she felt herself swoon, the room spinning beneath her. Momentarily unable to discern up from down, she caught herself on the edge of the altar, her knees losing strength.

John Kane grabbed her elbow, the elbow cradling the heart.

It bobbled in her grip…and fell.

The heart struck the altar with a dull clank and rolled across the slick marble, spinning on its iron surface, slightly wobbly, as if whatever liquid was inside had thrown it off balance.

Cassandra lunged for it.

“No!” Safia warned. “Leave it be!”

The heart spun a final time and came to rest. As it settled, it seemed to rock and swing slightly contrary, then stopped completely.

“Don’t touch it.” Safia knelt down, eyes even with the edge of the altar stone. The incense cloyed the air.

The heart rested in the exact position she had been holding it a moment before: ventricles down, aortic arch up and to the left.

Safia stood. She adjusted her body to match the position of the heart, again as if it were residing in her own chest. Once in position, she corrected the placement of her feet and lifted her arms, pretending to hold an invisible rifle in her hands—or a funerary incense burner.

Frozen in the pose of the ancient statue, Safia sighted down the length of her raised arm. It pointed straight along the long axis of the tomb, perfectly aligned. Safia lowered her arms and stared at the iron heart.

What were the odds that the heart would by pure chance settle into this exact position? She remembered the sloshing inside the heart, pictured its jittery spin, its final wobble at the end.