But Perkins turned to the largest of his squad. “Massarsky. Help the man out.”

The massive thick-necked mercenary slung off the strap of his semiauto and handed it to Garza, a Latina with cold eyes who had her hair tied back in a tight knot. She took it, but Drake noticed that her own weapon remained steady, aimed not quite at him but not away, either.

“Up you go,” Massarsky said.

Drake handed Jada his flashlight—he hadn’t yet drawn his gun tonight—and steadied himself on the edges of the horn-shaped entrance as he stepped up onto Massarsky’s back. Several flashlight beams converged on the octagonal stone he had identified. When he pressed his fingers against the stone, it did not move, but when he put one hand over the other and put his weight behind it, the octagon slid backward an inch and then two.

He thought of Sully and allowed himself to hope as he heard the grinding of stone and the heavy thunk of weights shifting in the walls. He dropped down from Massarsky’s back and peered into the chamber beneath the Soul Tower, but nothing was happening.

Then Jada tapped his arm, and he turned to see a square block sliding out of the wall to the left of the entrance. Dust fell to the ground. Flashlight beams swung over to illuminate the ten-inch square.

“There’s another one,” Corelli said.

Drake turned and watched the second stone, exactly opposite the first, sliding from the wall. With a loud double thud, the noises in the walls ceased. Henriksen pushed past Massarsky and examined the square on the left. Garza handed Massarsky his gun, but her gaze was on the other square. Jada had her flashlight on it, and now Drake joined her, running his fingers around the edges.

“There’s open space behind this one,” Henriksen said.

“Here, too,” Drake said. His fingertips touched what felt like a smooth stone cylinder, like a post or the axle of a wheel.

A wheel, he thought, gripping the square and trying to turn it. When he twisted to the right, he felt it give.

“Turn it!” Drake told Henriksen. He glanced over his shoulder and saw the big Norwegian doing just that.

Simultaneously, they rotated the squares until they wouldn’t turn any further. Drake felt something in the wall give way, and this time the grinding and thumping inside the walls was much louder, and he heard Jada cry his name at the same time he realized much of the noise was coming from the small room under the Soul Tower. The mercenaries were well trained—not one of them moved, ready for whatever happened next—but Corelli, Olivia, and Jada crowded in front of the horn-shaped doorway, and Drake had to crane his neck to get a glimpse inside.

The stone blocks that made up the floor of the small chamber were sinking in horizontal rows, each dropping a foot farther than the last, and Drake quickly realized they had released the mechanism they had been searching for. The floor had transformed into a set of stairs leading down into darkness.

“Massarsky,” Perkins said, “you and Zheng take point.”

The two mercenaries slipped through the horn-shaped entry, flashlights clipped to their guns, and started down the stone steps, weapons ready to fire. Drake had entered ancient temples and ruins before, and normally he’d have thought their caution unwarranted. But they were expecting an attack here. The Protectors of the Hidden Word would be waiting, but they didn’t know what kind of number to expect. It was possible that most of the hooded killers had died in their skirmishes in Egypt and on Santorini.

Still, better safe than dead.

Henriksen, Olivia, and Corelli followed the first half dozen mercenaries, ignoring Drake and Jada. Now that they had found the way into the emperor’s tomb, their former animosity was forgotten. Their full focus was on the yawning darkness below, and Drake understood why. As much as he wanted to find Sully, he had no problem letting some of the goon squad precede him. If the spooky ninja dudes were waiting, he was more than happy to let the hired guns take the first few hits.

They descended the stairs and found themselves in a long, sloping corridor. The rest of the mercenaries fell in behind Drake and Jada, though two of them hung back, staying to guard their exit. That made fourteen in Perkins’s squad and nineteen all together, counting Drake and Jada, Henriksen and Olivia, and Corelli. Nobody spoke as they moved along the corridor, listening for any sign of a potential attack coming from ahead and watching for hidden doorways.

The tunnel spiraled downward, taking them deeper, and then straightened out again and ran on for perhaps fifty yards before it ended in a vaulted chamber that caused them all to come to a halt. Two passages led away and farther downward from the chamber, and mercenaries were investigating both paths. But the rest of the group had focused elsewhere, and as flashlight beams illuminated the walls and ceiling, Drake stared in amazement.

“This isn’t man-made,” Henriksen said. “It’s a natural cave.”

Moss grew in thick patches on the walls. Stains on the solid rock showed the patterns where water had dripped down from above, and Drake shone his flashlight upward. He pressed himself against the wall alongside Olivia, who was doing the same thing.

“Do you see it?” she asked.

“A crevice,” he said.

Long, thick roots jutted from stone and earth and hung down, partially blocking the view, but Drake could see the glint of his light off jagged stone. Far above, where his beam could not reach, was a thin sliver of moonlight.

“Another one over here,” Garza called from the other side of the cave.

Corelli swore softly. “Olivia. Better have a look at this.”

Drake frowned and glanced at Henriksen, who had turned to look at Corelli. The bodyguard had his light trained on a blanket of moss, but there were hints of white among the green and brown.

“They’re flower buds,” Olivia said, a tinge of wonder in her voice.

“Not just buds,” Jada said, from a jagged alcove where the moss grew particularly thick. She shined her flashlight at a spot perhaps ten feet off the cave floor, where a trio of white flowers grew, dangling and half wilted.

“Those look familiar to you?” Drake asked.

Jada nodded. “Sure do.”

Henriksen came over to inspect them. “These aren’t white hellebore at all. They look similar—could be related—but the petals have a different shape.”

“And white hellebore can’t grow in moss with this little light,” Olivia added, coming up behind him.

Drake pushed against the wall and looked up, spotting another crevice. The moss was wet from the rain that ran down into the cave when it stormed. He pushed back and thrust his fingers into the moss, finding thick vines beneath it. He tugged them out to show the others.

“There you go,” Corelli said, as if to himself.

Perkins called for Henriksen, but Drake kept his eyes on the flowers. Cave hellebore, he thought, wondering if they had discovered a new species of flora.

“—no sign of diamond carvings or any other differentiating marks,” Perkins was saying.

Drake stiffened and turned. He stared at the two men and then at the two doors, and he realized something they obviously had figured out already. Two doors—two possible choices—this was the start of the fourth labyrinth.

“Jada,” he said. “Where’s the emperor’s tomb?”

Jada nodded slowly, but it was Olivia who answered.

“Maybe it was never here. Your professor friend in Oxford said they’d established it was here because they knew something was here. It made sense to assume it was the burial site—the underground palace.”

Corelli had gone over to the right-hand passage and begun to explore it, searching for markings the mercenary team already had established weren’t there. Drake liked the man less and less as the minutes ticked by. For a flunky, he seemed fairly presumptuous, almost as if he forgot from time to time that he was just an employee.

Henriksen glanced at Drake. “I have a theory.”

Drake nodded. “Let’s hear it.”

“It never made any sense to me that Daedalus would’ve marked the correct path through the Thera labyrinth.”

“He didn’t,” Jada said. “He marked the wrong path.”

“Granted,” Henriksen replied, blue eyes turned gray in the reflected illumination of so many flashlights. “But how long did it take us to figure that out? A man who would design such a puzzle would never offer so simple a solution. But what if those markings were added later, when it no longer mattered if intruders could find their way?”

“After the Thera eruption?” Drake asked. “Why bother?”

“No, it makes sense,” Jada said, and he could see it pained her to admit that Henriksen had a point. “If we’re going on the theory that there even was a golden hoard and that Talos—or someone—supervised the removal of Daedalus’s treasure from Thera, wouldn’t it go faster and much more smoothly if those moving the gold couldn’t get lost?”

Drake thought about it, then nodded reluctantly. “I guess. If they were really abandoning it.”

“Half of it had already collapsed,” Henriksen reminded him. “They wanted to move the gold to the fourth labyrinth, as Daedalus had done at least twice before.”

“It’s all about the gold with you, isn’t it?” Drake asked.

Henriksen smiled. “There are other treasures, but as far as motivations go, gold has its appeal.”

Drake knew he was supposed to hate the man, so he turned away before he let himself smile. Henriksen had a point. He had been motivated by gold plenty of times in his own life. This time, he had other interests: saving Sully’s life and getting vengeance for Jada’s father. The thought made the smile die on his lips.

“How do we choose a path?” Olivia asked. “I don’t think splitting up is a good idea.”

“Why not?” Jada asked. “There are plenty of us.”

Corelli snorted derisively. “Maybe because we’re not the only ones down here.”

Nobody acknowledged the comment. The mercenaries were already wary—they were paid to be—and Drake didn’t need reminding. He went over to the doorways into the two passages and studied them with his light. Runnels had been carved in the cave floor over time by rainwater from heavy storms searching for somewhere to drain. But in both of the doorways he saw that gutters had been cut into either side of the sloping passages. More of the runnels seemed to go to the left-hand passage, but that seemed like it must be a natural phenomenon. Still, the different levels of wear had him searching his mind. The water erosion triggered a thought.

Drake slipped off his pack and pulled out a sports bottle full of water. He uncapped it, went to the entrance of the left passage, and knelt to pour a few ounces across the threshold there. Jada had followed, giving him the benefit of her flashlight.

“What the hell are you doing?” Corelli asked.

“Thinking,” Drake replied. “Try it sometime.”

He went to the right-hand passage and repeated the process, nodding as he saw the water running into tiny cracks and pooling into depressions as it trickled down the slope into the tunnel.

“This way,” he said, standing and going back to stow the water and slip his pack back on.

“What was that?” Henriksen asked. “Are you Tonto now?”

“If they had so much gold then they had to mark the path for workers to carry it all out of the labyrinth on Thera, there was a hell of a lot of traffic going in and out of here at one point,” Drake explained. He pointed to the right-hand passage. “There’s a hell of a lot more wear on that side and hardly any erosion on the left. Not a lot of foot traffic that direction.”

Henriksen considered that but looked unsure.

Drake shrugged. “Do what you want. Sully’s here somewhere. Jada and I are going to find him.”

He glanced at her to make sure he had the right to speak for her, but she already was following. She had put her hair up in a ponytail, magenta on black, and without it veiling her features, her face had a soft vulnerability that was deceiving. But when she met his gaze, he saw the familiar determination in her eyes and knew there was no turning back for either of them.

As if there ever could have been, he thought.

“The man makes sense,” Perkins said.

Henriksen glanced over at the mercenaries, who had spread out, some of them still investigating the cave while others were on alert for any sign of approach.

“The logic is solid, Mr. Henriksen,” Perkins continued. “I can’t say we’re going to be able to determine which path is correct at each turn in the labyrinth, but right now, I advise we take the tunnel on the right.”

Henriksen glanced at Olivia, but her face was an unreadable mask.

“Right it is,” he said. “But everyone be on guard. The protectors know these corridors intimately. And I have no doubt they have doors we’ll never see. Perkins, make sure someone is covering the rear.”

“Yes, sir,” Perkins said, gesturing for two of his people to guard their flank.

But that was the problem in a labyrinth full of hidden chambers and secret passages. It was impossible to know where an attack would be coming from. Anything could be hiding in the shadows.

21

They set off down the sloping tunnel in twos, as before, and the twists of the labyrinth quickly revealed themselves. Several times they were able to find the right path by measuring the wear on the floor, but in other places they were forced to explore wrong turns for long minutes before realizing they had chosen poorly.

This labyrinth differed significantly from the others in that it was a combination of man-made tunnels and natural caves. In another of the caves they passed through they found moss growing and fissures that led up to the surface, and Drake wondered how far underground they had traveled. There were vines as well, but only small blossoms of cave hellebore, nothing in full bloom.

A curving stone staircase had been carved into the side of a large cavern that dropped away precipitously on the right. Drake kept a hand on Jada’s shoulder as they went down the stairs, feeling the presence of the mercenaries behind him. He had been careful to make sure that Corelli preceded them down, not trusting the man to follow. At the bottom of the steps, they found the first writing on the walls and familiar paintings of cave hellebore, as well as the symbol of the four interlaced octagons that stood for the four labyrinths.