“And my head hurts,” Haru said, kneeling and parting her hair to show Reiko a red lump on the back of her scalp.

Perhaps the arsonist had abducted Haru from the orphanage, beaten her, and dragged her across the temple grounds-which would account for the scrapes and bruises-and put her in the cottage. Then Haru had somehow managed to escape the burning building, Reiko theorized. The head wound could explain her memory loss. Reiko’s doubts began to crumble. Maybe Haru hadn’t set the fire. Her injuries were evidence that she could have been an intended victim of it.

Haru wrapped herself in her kimono. She huddled on the floor, fretting, “I’m so afraid someone will hurt me again. I’m so afraid of dying!”

Her plight moved Reiko to tears. Unless facts later proved that Haru was guilty, Reiko must give her the benefit of the doubt. Impulsively, Reiko embraced Haru.

“You’re not going to die, if I can prove that you’re innocent and find the real arsonist,” Reiko said.

Edo Jail loomed above a filthy canal amid the slums of Kodemmacho, in the northeast sector of the Nihonbashi merchant district. Watchtowers topped its crumbling stone walls. Inside, dilapidated offices and barracks surrounded the fortified dungeon where jailers tortured confessions out of prisoners and criminals awaited execution. The morgue received the bodies of citizens who perished in natural disasters or from unnatural causes. Yet hidden within this realm of death, a small green oasis flourished. In a fenced courtyard, a garden grew in neat rows marked by bamboo stakes; butterflies and bees flitted. Here Sano found his friend Dr. Ito tending his medicinal herbs. Sano walked along the garden’s border, enjoying its fresh aromas. He could almost imagine himself in the countryside, rather than in a place shunned by society.

“Good morning, Ito-san,” he said, bowing.

A tall, thin man in his seventies, Dr. Ito bowed and smiled. His short white hair gleamed in the sunlight; perspiration filmed his lined, ascetic face. “Welcome, Sano-san. I have been awaiting your arrival.”

Dr. Ito, once a respected physician to the imperial family, had been caught practicing forbidden foreign science, which he’d learned through illicit channels from Dutch traders. Usually the Tokugawa punished scholars of Dutch learning with exile, but the bakufu instead condemned Dr. Ito to permanent custodianship of Edo Morgue. There he continued his scientific experiments, ignored by the authorities. He also administered medical treatment to the staff and prisoners, and his expertise had often benefited Sano’s investigations.

Wiping his hands on his dark blue coat, Dr. Ito rose with the stiff movements of old age. “How is Masahiro-chan?”

“Many thanks for inquiring about my miserable, inferior child,” Sano said, observing the polite custom of deprecating one’s offspring. “His size, his voice, and his demands grow daily.”

A twinkle in Dr. Ito’s shrewd eyes acknowledged the paternal pride behind Sano’s modesty. “I am glad to hear that. And I hope the Honorable Lady Reiko is well?”

“She is,” Sano said, but the mention of Reiko unsettled his thoughts.

During the trip from Edo Castle, he’d begun to have misgivings about asking her to help with the investigation. Might her over eagerness frighten Haru and ruin their chances of getting the truth from this important witness and possible suspect? Sano valued Reiko’s excellent intuition, but he needed an impartial judge to question Haru, and he belatedly understood how Reiko’s personal biases might interfere with her objectivity. Sano wished he’d asked Reiko to wait until they could go to Zōjō Temple together, so he could listen in on the interview with Haru. Although Reiko had never yet failed him, he feared what might happen with this investigation.

Dr. Ito said, “Is something wrong, Sano-san?”

“No, nothing,” Sano said, not wanting to burden his friend with his troubles. He turned the conversation to the purpose of his visit. “Have you received the bodies from the fire at the Black Lotus Temple yet?”

Dr. Ito’s expression turned serious. “Yes. And I regret to say that my examination has revealed some discoveries that may complicate your work.”

He led Sano to the morgue, a low building with peeling plaster walls and an unkempt thatched roof. Inside, a single large room held stone troughs used for washing the dead, cabinets containing tools, and a podium heaped with books and papers. Dr. Ito’s assistant Mura, a man in his fifties with gray hair and a square, intelligent face, was cleaning knives. He bowed to Sano and his master. Three waist-high tables each held a human figure covered with a white shroud. Dr. Ito walked to the largest body.

“Commander Oyama,” he said, then beckoned his assistant.

Mura stepped forward. He was an eta, one of the outcast class that staffed the jail as wardens, torturers, corpse handlers, and executioners. The eta’s hereditary link with death-related occupations such as butchering and leather tanning rendered them spiritually contaminated and barred them from contact with other citizens. Mura, who performed all the physical work associated with Dr. Ito’s studies, removed the shroud from Police Commander Oyama.

Although Sano had learned to control his aversion to the dead during past examinations, he felt a sense of pollution as he beheld the pale, naked corpse with its thick torso and limbs. Oyama’s glazed eyes and gaping mouth gave him an imbecilic expression that belied the wits of a man recently responsible for enforcing the law in a city of one million people.

“Turn him over, Mura,” said Dr. Ito.

The eta complied. Dr. Ito pointed to the back of Oyama’s head. The hair had been shaved away, revealing a hollow in the scalp behind the left ear, with reddened, broken flesh in the center. “A blow cracked his skull,” Dr. Ito said.

Because the examination of corpses and any other procedures that smacked of foreign science were illegal, Sano had forgone a detailed scrutiny of Oyama while at the Black Lotus Temple; he’d looked just long enough to identify the commander’s face and hadn’t noticed the injury. Now he said, “Could it have happened after Oyama died?”

Dr. Ito shook his head. “There was blood in his hair and on his skin before Mura washed him, and the dead don’t bleed. Oyama was alive when the blow was struck by an object with sharp edges. An injury of such severity is usually fatal. He wasn’t burned, and his color exhibits none of the pinkness I would expect to see if he’d died from breathing smoke. Therefore, I conclude that the blow, not the fire, killed Oyama.”

“I found nothing resembling a weapon when I searched the site of his death,” Sano said. “But it’s clear that his murder was deliberate instead of an accidental result of arson. The fire must have been set to disguise the murder.”

Blowing out his breath, Sano shook his head in consternation. He’d hoped that Oyama’s death was a simple matter of being in the wrong place at the wrong time. Now Sano saw the scope of the case expand beyond the boundaries of the Black Lotus Temple. The list of potential arson suspects, previously headed by the orphan girl Haru and limited to the temple community, grew to include the associates of a man who must have made many enemies during his life.

As if reading his thoughts, Dr. Ito gave Sano a sympathetic look, then said, “I’m afraid that there wasn’t just one murder before the fire was set.”

Dr. Ito walked to the second table. Mura uncovered the body of the dead woman. A fetid odor of burnt, decaying flesh filled the air. Sano’s stomach lurched. He swallowed hard as he viewed the corpse. With her garments removed except for charred strips of cloth adhering to her, the woman looked even worse than she had yesterday. She lay on her right side, bent at the knees and waist, arms angled. Burns ranging in color and texture from blistered, scabrous red to black cinder covered her limbs, torso, face, and hairless scalp. When Mura turned the dead woman on her other side, Sano saw unscathed areas on the newly exposed portions of skin.