This was where Lord Matsumae had imprisoned the outsiders who’d arrived in Ezogashima during his madness. Here they’d been tortured and killed. The troops she’d seen here yesterday had been trying to clean the place up, probably in case Sano should see it. But the troops had taken ill, leaving their job unfinished and the truth plain as day to Reiko.

She was standing in a slaughterhouse.

A slaughterhouse to which her son had been brought.

“Masahiro!” she cried, running through the maze, peering in the cells. All were empty but for signs of carnage.

“Here!” Wente pulled her up a staircase that led to a square hole in the ceiling.

They emerged into the keep’s second story. Light came from gaps around the shutters and chinks in the plaster. Reiko rushed through unfurnished rooms partitioned by sliding walls. In the last one she found a strange object, a big, square box with a wooden top and bottom, and sides made of crisscrossed iron bars. It was a cage for a large animal-or a small human. But no one was inside. Reiko let out a cry. She saw an image of Masahiro huddled in the cage, his eyes filling with joy as he recognized his mother who’d come to save him. She flung herself at the cage.

The image vanished. The cage was empty again except for hay, the door open. Nearby lay a quilt stained with blood.

“No!” Reiko wailed.

She snatched up the quilt and pressed her face to it, inhaling the sweet, earthy, little-boy smell of Masahiro and the ranker odor of his blood. She wept, assailed by a terrible vision of troops beating him to death.

Wente knelt beside her, patted her back, and murmured words of sympathy in Ezo language. She reached inside the cage, removed something from the hay, and put it in Reiko’s hand. It was a leather drawstring pouch that contained a figurine carved from wood, a brightly painted horse clad in battlefield armor. The horse belonged to a set of toy soldiers that Reiko and Sano had given Masahiro. Reiko held it to her heart and sobbed harder. This was all she had left of her son.

He was gone.

She was too late.

Sano had spent all day searching the rest of the palace and questioning the Matsumae clan members, officials, troops, and servants. He’d found no clues, but then he hadn’t really expected to; the crime wasn’t the kind that would leave evidence such as wounds on the culprit or blood-stained clothes in his possession. A vial of arrow poison was easily disposable, and nobody had left a written confession.

Except Lord Matsumae.

Sano’s interviews had also turned up nothing. The witnesses were nervous and reluctant to talk. Gizaemon had listened in on all the conversations, even though Sano had repeatedly asked him to stand out of earshot. Maybe the witnesses didn’t want to say anything that would incriminate him, Lord Matsumae, themselves, or their friends. Sano and Detective Fukida returned to their quarters at dusk empty-handed.

Except for Lord Matsumae’s diary.

The blizzard had stopped, and the sky was dark, but the snow gave the landscape a spectral luminescence. A lantern over the door spilled a golden glow over high white drifts piled up against the guest quarters. Gizaemon left Sano and Fukida with the lone guard stationed in the entry way. The northern plague must have sent the others to bed.

“See you at the funeral tomorrow, Honorable Chamberlain,” Gizaemon said.

After he and Fukida had removed their shoes, Sano went to the chamber he shared with Reiko. Her blanket-covered figure lay in bed in the darkness. He decided to let her sleep. She needed rest, and he didn’t have any good news for her. He joined his men in their room; Hirata, Marume, and the Rat had returned. They’d spread their coats upon drying frames over the charcoal braziers. Sano added his to theirs. The room was steamy and redolent of wet fur. Marume poured hot tea and laid out a dinner of cold rice balls, dried salmon, and soup with seaweed and boiled lotus roots. As he and the other men tore into the food, Sano forced himself to eat. Fear for Masahiro chased through his anxiety about the investigation. He felt the snow weighing upon the roof, suffocating him.

Fukida explained about the plague. “Now would be the time to cut and run, while the troops are sick and there aren’t so many around. But we don’t exactly have anyplace to go. Too bad, because we aren’t making much progress on this investigation.” He asked Hirata and Marume, “What about you?”

“We went hunting with the Ainu,” Hirata said.

“The what?”

“Ainu. That’s what the natives call themselves.” Hirata added, “They saved our lives. We owe them at least the courtesy of using their proper name.”

He sounded defensive on their behalf, Sano observed. His interest in the Ezo-or Ainu-seemed to have been strengthened by the hunt. “Did you get anything?”

“One deer,” Hirata said.

“I meant information pertaining to the murder,” Sano said.

“Oh. Well.” Hirata told how Chieftain Awetok had explained his way of disciplining his people and his ritual for driving out the evil spirits that made them behave badly. “He said he didn’t kill Tekare. I think he’s telling the truth.”

“What about her husband?” Sano asked.

“The same with him.”

But Hirata looked into his tea instead of at Sano. Now Sano knew something more had happened on the hunt besides a talk about native customs and shooting a deer. Something that incriminated one or the other native, that Hirata didn’t want to tell Sano. Hirata’s loyalties had become divided.

“Well, I’ve found a clue,” Sano said, “although it’s not exactly what I wanted.”

He produced the diary. Hirata read it first, then the detectives. They all reacted with surprise.

“This is the most incriminating evidence we’ve got against anyone,” said Hirata.

“Especially that last part about the spring-bow,” Marume said. “It sure sounds like Lord Matsumae is our killer.”

“It may be proof of intention, but not of deed,” Sano said. “The diary doesn’t say whether he actually carried out his plan to murder Tekare.”

“Do you really think he did?” Fukida sounded doubtful. “Then pretended to think someone else had killed her? Held the whole island hostage? And agreed that you should investigate the crime that he committed himself? It sounds insane.”

“Which Lord Matsumae is,” Hirata said.

A new idea occurred to Sano. “Sometimes a disturbed mind hides painful things from itself. And Lord Matsumae’s mind seems to have been disturbed long before Tekare died.” Sano opened the book and read aloud the passage about the wine and the pipe filled with native herbs. “I wonder what those herbs were? And what was in that wine?”

“Poisons that made him forget he killed Tekare and made him think he’s possessed by her spirit,” Marume suggested.

Sano wondered if enslaving and ruining Lord Matsumae had been another form of Tekare’s revenge against the Japanese who’d mistreated her. “Maybe they also drove him to all the other violent acts he’s committed since her death.”

“Supposing he did kill her,” Fukida said, “why would he have let you search the palace and find his diary?”

“Maybe a part of him wants to be caught and punished,” Hirata said, “and leaving his diary for you to find is his way of confessing.”

“I wonder what the spirit of Tekare would do to him if she found out that he killed her,” Fukida said.

“What do we do next?” Marume asked.

Sano had been pondering that question ever since he’d found the diary. He’d delivered many criminals to justice, but never one who’d been holding him prisoner. “Lord Matsumae won’t take kindly to my telling him that he’s the killer I’ve been commissioned to catch. Particularly if he doesn’t remember killing Tekare and believes he’s innocent.”

“We could arrest him,” Marume said.

Nobody laughed at his joke. The time might come when they must try to take Lord Matsumae by force. The samurai code of honor didn’t excuse them from suicide missions.