They scurried over to the base of the building and crouched in the shadows. Midori heard footsteps inside, and the scrape of doors sliding. Then a male voice said, “I’ll take her.” Another said, “That one will do for me.” Soon Junketsu-in exited the building, alone. She walked toward the main hall. Midori was torn between investigating the mysterious activities here, or spying on Junketsu-in. Afraid of the abbess, she decided to stay.

Low murmurs came through the window above; Midori couldn’t make out the words. Toshiko rose, poked her finger through the bars, pierced the paper pane, and gingerly tore a hole in it. While Midori watched, daunted by her boldness, Toshiko peered into the hole.

“Look!” she whispered excitedly.

After glancing around to make sure nobody was watching, Midori stood and looked through the hole. Inside were a nun and one of the samurai who’d come with Abbess Junketsu-in. The samurai had stripped nude. He was kneeling, while the nun hunched before him, sucking his organ. He groaned, caressing her shaved head. Midori gasped in shock.

Toshiko tugged her arm. “Let’s see what’s happening in the other rooms.”

They crept to the next window, where Toshiko tore another hole. In this room they saw a naked monk crouched on all fours. The other samurai knelt behind him, thrusting into his buttocks. Recalling the exchange she’d observed between Junketsu-in and the two samurai, Midori realized that the men had been paying for sexual services and choosing their companions. The temple was running a brothel for rich patrons.

“Have you seen enough?” Toshiko whispered. “Can we leave?”

Midori would have liked nothing better than to flee the temple, but she doubted that Reiko or Hirata would think much of what she’d learned so far. Prostitution outside the Yoshiwara licensed district was a crime, but it revealed nothing about the murders or the Black Lotus’s plans.

“We can’t go yet,” Midori told Toshiko. “Come this way!”

They stole through the grounds, back to the site of the burned cottage. Crouching at the edge of the hole, they peered inside. Midori saw a shaft with plank walls; a wooden ladder extended down one side into a deep pit. Dim light shone at the bottom, and she heard a distant clattering noise.

“There’s something in there. It’s dark,” Toshiko whimpered. “I’m afraid to go down.”

So was Midori, but she must be brave. “You can wait for me here,” she said with more confidence than she felt.

“But I’m afraid to be alone.”

“Then you’ll have to come with me.”

Midori began climbing down the creaky ladder. The dark shaft enclosed her. As she descended, the air grew cooler and damper, exuding the odor of soil. A panicky, trapped feeling built inside Midori. She gripped the sides of the ladder and her feet fumbled for the rungs while she imagined hands reaching up from the darkness to grab her. Reaching the bottom, she found herself in a cave. The light came from oil lamps mounted on the reinforced walls of three tunnels that joined where she stood. A moment later, Toshiko came scrambling down the ladder.

Having her friend by her side renewed Midori’s courage. “This way,” she said, picking a direction at random.

Treading softly upon the earth floor, they started down a tunnel. The steady beat of the clattering noise echoed around them. Air gusted from holes in the ceiling, and a strong odor of fish and pickled radishes permeated the atmosphere. Rooms lined the tunnel. Midori peeked through the open doorway of one and saw ceramic urns stacked to the ceiling. The next rooms contained rice bales, and the next, water barrels.

“These must be the provisions we saw them bringing into the temple,” Midori said. The cool temperature would preserve the food, but she didn’t understand why the sect would amass so much, or bother hauling water underground.

Toshiko gazed down the tunnel, her eyes alert and frighted. “Someone’s coming!”

Midori heard the footsteps in the distance. She ducked into the room containing the water barrels, pulling Toshiko with her. They watched six priests march by. After the group passed, they started down the tunnel again.

“Where are we going?” Toshiko whispered.

“I guess we’ll follow the noise.”

This grew louder as they wound deeper into the subterranean complex. They passed more pantries, rooms lined with mattresses set on wide shelves, and junctions where the tunnel branched. At one junction, a shaft rose to ground level. Four nuns came down its ladder. Midori and Toshiko leapt back into the tunnel just in time to hide.

“Let’s go back up,” Toshiko pleaded.

“Not yet.”

The clatter rose to a shuddering racket. Through it Midori heard resounding metallic clangs and eerie cries. Now they came upon a spacious hollow. Inside, Midori saw what looked to be a gigantic machine composed of pleated, tubular cloth bellows, wooden wheels, and a vertical iron conduit as wide as a tree trunk running through the ceiling. Ten muscular priests pumped the bellows and turned cranks.

“They’re pumping air in from outside so people can breathe down here,” Midori deduced.

She and Toshiko slipped past the hollow. They rounded a corner, and a deafening cacophony burst upon them, accompanied by a powerful reek of urine and rank earth. Down the passage, shaven-headed men and women shoveled, swung pickaxes, erected beams and walls, and hoisted loads of dirt up a shaft, building new tunnels. Sweat and grime soiled their clothes; iron chains shackled their ankles. Torches flared through dust clouds. Priests armed with clubs strolled through the scene, hitting workers who paused to rest. Pained cries rent the air.

“I think I’ve seen enough,” Midori said, appalled to discover that Reiko’s tale of slavery in the temple was true, and increasingly afraid of getting caught. “Let’s go back up.”

Hurrying back through the tunnels with Toshiko, she followed the route by which they’d come, but somewhere she took a wrong turn into unfamiliar territory. Here, the passage stank of rotten fish, and Midori heard grinding noises coming from a room. Signaling Toshiko to stand back, she stole up to the doorway and peeked inside. A man stood at a long table against the wall, writing. It was Dr. Miwa.

Fear clenched Midori’s stomach as she observed that the room was some sort of workshop, furnished with equipment strange to her. A nun was lifting small, dead fish from a basin of water and dropping them into a ceramic pot. Another nun pounded the fish with a sharp-bladed chopper, while more nuns strained slimy pulp through cloths and gathered the liquid in jars. Midori recognized the fish as fugu-puffer fish. Everyone knew that fugu was poisonous and its sale illegal in many places. What could the Black Lotus be planning to do with the extract?

Suddenly Toshiko gasped, clutching Midori’s arm, as footsteps approached. The girls scurried around a corner, peered cautiously out, and watched three priests cross a junction some twenty paces away. One was High Priest Anraku. The others carried lanterns. Midori remembered the ceremony and Anraku’s fathomless eyes, hypnotic voice, and unsettling touch, his sexual arousal and her own. She wanted to run fast and far from him, but he was the heart of the Black Lotus and important to her mission.

“We’ll follow him,” she told Toshiko.

They hurried after Anraku. Suddenly a group of nuns came around a corner and straight toward them. Toshiko shrank back, but Midori pulled her forward, murmuring, “Keep going. Act like you belong here.”

The nuns passed, bobbing perfunctory bows, which Midori and Toshiko returned. Ahead, Anraku and the priests entered a room. Midori and Toshiko huddled near the door.

“How many pieces?” Anraku’s voice said.

A priest replied, “Our samurai patrons have donated enough to arm everyone in the temple and all our brothers and sisters outside.”