“There’s a message from the chamberlain,” Arai said. “He requires your assistance on an urgent matter. He wants you to meet him at the Edo Castle racetrack immediately.”

Honor, duty, and friendship propelled Hirata to the racetrack. It wasn’t far from his estate, but by the time he arrived with two detectives and they dismounted from their horses inside the gate, his wounded leg ached even worse than usual. He looked across the compound and saw Sano at the opposite end, talking to a group of officials. Hirata drew a deep breath. His infirmity magnified the distance between him and Sano tenfold. He gathered his strength.

“Come on,” he told Detectives Arai and Inoue.

As they began the long walk, Detective Arai spoke in a quiet, offhand voice, “We could ride.”

His men always tried to make things easy for him. “No,” Hirata said.

This was one of his rare public appearances. Most of his colleagues hadn’t seen him since he’d been injured, and he had to demonstrate that he’d made a full recovery. To show any weakness would diminish his status. While he labored toward Sano, the officials scattered around the track bowed to him, and he nodded in acknowledgment. He feared that everyone could see how hard he was struggling not to limp. Sano, Marume, and Fukida hurried to meet Hirata and his detectives.

“Honorable Chamberlain,” Hirata said, trying not to gasp for breath.

“Sōsakan-sama,” said Sano.

They exchanged bows; their men, once comrades in the detective corps, greeted one another. Hirata was glad to see Sano because he rarely did; perhaps a month had passed since they’d last met. Although Hirata was technically still Sano’s chief retainer, their new duties kept them apart. Now, a stiff formality had replaced the camaraderie they’d once shared. Relations between them had been awkward since Hirata’s injury.

Sano signaled their men to move off and allow them some privacy. “I hope all is well with you?” Sano said. Concern sobered his gaze as he regarded Hirata.

Perhaps the fact that Hirata had saved Sano’s life should have brought them closer together, but it had had the opposite effect. That Hirata had done only what a samurai owed his master didn’t exempt Sano from guilt because he was whole and Hirata maimed. Sano’s guilt and gratitude, and Hirata’s loss, filled a wide gulf between them.

“All is very well with me.” Hirata stood as straight as he could; he hoped Sano wouldn’t read his pain etched on his face. He didn’t want Sano to feel worse; for Sano to suffer distressed Hirata deeply. “And you?”

“Never better,” Sano said.

Hirata noticed that Sano had lost the anxious, careworn air that had marked him in his early days as chamberlain. Indeed, he looked like himself in the old days when he and Hirata had first worked together. But Hirata didn’t want to think about those days.

“What happened?” Hirata said, gesturing around the track.

“Ejima Senzaemon, chief of the metsuke, died during a race,” Sano said. “Lord Matsudaira suspects foul play and has asked me to investigate.” He described his meeting with Lord Matsudaira, and the preliminary inquiries he’d conducted.

“So far it doesn’t sound as if Ejima’s death was murder,” Hirata said, interested yet skeptical. “Can it and the earlier deaths really be part of a plot against Lord Matsudaira, or is he imagining a plot in a set of coincidences?”.

“That’s what I mean to find out,” Sano said. “I called you here because I need your help.”

Even as Hirata experienced an ardent wish to work with Sano on such an important case, he worried that it would require more strength than he had. Hirata saw Sano appraising his gaunt figure, and realized that Sano feared he was physically unable to work. Mortification sickened Hirata. He couldn’t let Sano think him weak and useless.

“It will be an honor to serve you,” Hirata said. He would help Sano or die trying. “Where do you want me to start?”

“You can start by taking Ejima’s body to Edo Morgue,” Sano said in a low voice that the witnesses and soldiers wouldn’t overhear. “Ask Dr. Ito to examine it.”

Once a prominent, wealthy physician, Dr. Ito had been sentenced to lifelong custodianship of Edo Morgue as punishment for conducting scientific experiments that derived from foreign lands, a crime strictly forbidden by Tokugawa law. He’d helped Sano on past investigations.

“Have him find out the exact cause of death,” Sano clarified. “That’s key to establishing whether it was murder.”

“I’ll go right away,” Hirata said.

He sounded as eager as ever to do Sano’s bidding. But Sano saw the pain and worry he tried to hide, and sensed him wondering if he could withstand the journey to Edo Morgue, all the way on the other side of town. Sano, who hadn’t seen Hirata in a while, had been dismayed to observe how fragile he still was. Sano didn’t want Hirata taxing his health or getting hurt again for Sano’s sake. But although Sano would rather go to Edo Morgue himself, it was too big a risk: Should the chamberlain of Japan be caught participating in the forbidden science of examining a corpse, he would fall much farther than Dr. Ito had. Nor could Sano take back his request and shame Hirata. He needed Hirata as much as Hirata apparently needed to prove himself capable of the duty that the bond between samurai and master required.

“Bring the results of Dr. Ito’s examination to me as soon as possible,” Sano said. “If I’ve finished questioning witnesses by then, I’ll be at my estate.” He couldn’t let the government collapse while he investigated a murder that might not be murder. “Then we’ll report to Lord Matsudaira. No doubt he’s anxious for news.”

One wing of the Court of Justice contained rooms where the magistrate and his staff conferred with citizens seeking to resolve disputes that involved money, property, or social obligations. Here Magistrate Ueda had sent Yugao. As Reiko walked down the passage, she heard raucous male laughter from an open door. She peered inside.

The room was a cell enclosed by sliding paper-and-lattice walls, furnished with a tatami floor and a low table. Yugao stood between the two guards that Reiko liked the least in her father’s retinue. One, a thickset man with squinty eyes, pawed Yugao’s cheek. The other, athletic and arrogant, groped under the skirt of her hemp robe. Yugao scrambled away, but the men caught her. They yanked at her robe, squeezed her buttocks and breasts. She strained at the shackles that bound her hands while she kicked her bare feet at the men. They only laughed more uproariously. Her face was tense with helpless anger.

“Stop that!” Reiko exclaimed. Bursting through the door, she ordered them, “Leave her alone!”

They paused, annoyed at the interruption. Their faces showed dismay as they recognized their master’s daughter.

“The magistrate will be displeased to hear that you’ve been taking advantage of a helpless woman in his house,” Reiko said, her voice sharp with ire. “Get out!”

The guards slunk off. Reiko shut the door and turned to Yugao. The woman slouched, her face concealed behind her tousled hair, her robe hanging off her shoulder. Pity filled Reiko.

“Here, let me fix your clothes,” she said.

As she touched Yugao, the woman flinched. She tossed back her hair and stared at Reiko. “Who are you?”

Reiko had expected Yugao to be thankful for her protection from the guards, but Yugao was wary, hostile. Seeing her at close view for the first time, Reiko noticed that her complexion was ashen from fatigue and malnourishment, her flinty eyes shadowed underneath, her lips chapped. Harsh treatment by the jailers had surely taught her to be leery toward everyone. Although she was accused and perhaps guilty of a serious crime, Reiko felt her sympathy toward Yugao increase.