It was featureless, about half a meter square. “This is warmer than the others, suggesting it must be more directly exposed to the sun.”
“Is it a way out?” Miyuki turned on her own flashlight.
“I hope so. I just don’t know how to open it.” Karen closed her eyes.
“What are you thinking?” Miyuki asked.
Karen opened her eyes. “I’m not sure. In the other pyramid, the temple’s altar was the access point. The sculptured snake head was the key.”
“Yeah?”
“Think symmetry. Think larger. In the ruins of Chichen Itza on the Yucatan peninsula, the main pyramid casts a snake shadow during the equinoxes, a winding shadowy body that connects to a carved stone snake head at its base.”
“I don’t understand.”
Karen kept talking, intuiting that she was close to an answer. “The serpent’s head was the entry point. This connected to a long lava tube…perhaps representing a snake’s body.”
Miyuki nodded. “If you’re right, then we’re in the snake’s tail.”
“We were swallowed by a snake, traveled through its belly, and now must complete the digestive process.”
“In other words, we must find this snake’s butt.”
Karen laughed at the dead seriousness with which Miyuki had spoken these last words. “Yep.” Karen turned. The opening to the stairwell lay directly opposite her. She twisted around. The warm stone was in direct line with the opening. A straight line. She placed a hand on the stone. “This is the tip of the tail. The end of the snake.”
“Right. You said that. It’s the way out.”
“No! We aren’t paying attention to anatomy. A snake’s butt isn’t in the tip of its tail. It’s on its underside!” Karen pointed to the floor. “Its belly!”
Miyuki stared at her toes. “To go up, we must go down.”
Karen dropped to her knees on the stone floor. It wasn’t a slab, but fitted blocks, like the walls. She crawled forward, starting at the warm brick and aiming for the stairwell, wiping the water and debris from the floor as she went. It had to be here!
Her fingers brushed over something rough on the smooth stone. She froze for a heartbeat, then rubbed the spot, praying.
Miyuki knelt near her. “What is it?”
Karen moved aside. “The snake’s butt!”
Imprinted into the smooth block was a carving: a star-shaped depression.
“Get me the crystal!”
Miyuki rushed over and retrieved her bag. She dragged it back, then zipped open the side pouch and pulled the star-shaped crystal out. She had to use both hands. Grunting, she hauled it over to Karen. “Here.”
Karen rolled to her belly and lugged the star into place in the depression. It was a perfect fit. She held her breath, ready for anything. Miyuki stood by her shoulder, a fist at her throat.
Nothing happened.
Karen sat up on her knees. “What’s wrong? What aren’t we doing right?”
“Maybe the mechanism is broken.”
Karen did not even want to think of that possibility. She knew that by now the lower passage must be totally flooded. There was no way back. They were trapped here. She felt tears coming to her eyes. Her throat tightened.
“How was the crystal supposed to trigger the secret passage?” Miyuki asked, still pondering the riddle.
“I…I don’t know.”
“Didn’t you say something about the other mechanism being pressure-sensitive?”
Miyuki’s words sank through Karen’s hopelessness. She remembered how the altar stone had moved back up into the ceiling after Miyuki had jumped off it. The mechanism must have been pressure-sensitive, responding to the change in weight.
Karen stared down at the crystal. It was heavy, unusually so. But if the secret door here was triggered by weight, then why hadn’t it triggered when she’d first walked across it?
Then it dawned on her.
“Get off! Get off!” she yelled at Miyuki, waving her away from the stone block and crystal. “We weigh too much!”
“What?” Miyuki said, but backed away.
Karen moved beyond the edge of the block. “It must be balanced to the weight of the crystal. No more, no less.”
Both women stepped away. Karen stared hard at the crystal. Still nothing. She felt a scream of frustration building in her chest. What were they missing?
She turned in a slow circle. The walls were blank and featureless. No answer—
She turned again. No wall sconces. No place to hook a torch. “Darkness,” she mumbled. “The belly of a snake is hidden from the sun.”
“What?”
“Turn off your flashlight!”
“Why?”
“Trust me!” Karen thumbed off her penlight.
Miyuki followed suit, plunging them into perfect darkness. “Now what are—”
A sharp grinding interrupted Miyuki. Rock on rock. Karen froze, praying she was right. In the hushed silence she reached out and fumbled for Miyuki’s hand.
Then a spear of sunlight appeared, sprouting from the floor to strike the ceiling. Blinking against the glare, Karen dropped to her knees. The stone block with the crystal was sinking into the floor.
Karen crawled to the edge and peered into the deepening hole. The shaft of sunlight came from a narrow crack in the left wall of the pit. As she watched, the block sank away and the crack grew wider, opening a side tunnel.
Light poured in.
Karen’s vision blurred with tears of relief. It was the way out!
Below, the stone block finally stopped its descent with a grating sound, leaving the side passage wide open.
Karen rolled to her side and waved for Miyuki to go first. “Let’s get out of here.” It was only a drop of a couple meters.
Grabbing her satchel, the Japanese professor, smiling with relief, clambered into the pit. She landed and crouched down, peering through the side tunnel. “It’s only a few feet! I see the sun!” Miyuki crawled into the passage, giving Karen room to come down.
Karen did not pause. She jumped into the pit. The sunlight blinded her for a moment, then she saw the blue sea beyond the short tunnel, shining bright. “Thank God!” She bent and entered the side passage. Twisting around, she grabbed the crystal star. She was not leaving behind her prize.
The star seemed much lighter now. She was able to pick it up with one hand. As she held it, the stone block ground up behind her and Miyuki, closing off the doorway back to the inner chamber. Turning to the exit, she shoved the artifact into her hip pocket. Free of her fingers, it sank like a lead weight, straining her pants’ seams.
“Don’t move!” someone ordered in Japanese.
She froze.
A second man jumped off the pyramid step behind her. With relief, she saw that he wore a police uniform with the Chatan emblem on his sleeve. It wasn’t the looters. She was ordered to face the stone, palms on the