Narumi took off her fins and sat down on the rock. “I’m glad you liked it. But wasn’t there something else you wanted to talk to me about?”
Yukawa smiled knowingly and sat down next to her. His eyes were fixed out on the horizon. “Summer’s ending soon,” he said.
“Mr. Yukawa?”
“My detective friend found Hidetoshi Senba. I met him yesterday, in fact. He’s in the hospital with an incurable brain tumor. He doesn’t have long to live.”
Narumi felt a lump form in her chest, an uncomfortable tightness she couldn’t swallow or spit out. Her face drew tight.
“I’m sure you’re wondering why a physicist would go so far out of his way. I wonder that myself. It’s really none of my concern.”
Narumi searched for something she could say that would explain it all away. But at the same time, she realized there weren’t any magic words. He already knew everything.
“The man mostly responsible for taking care of Senba was none other than the detective who arrested him sixteen years ago. Tsukahara had retired from the police force, but that one case still bothered him. I’m not sure what the two of them spoke of, but I imagine that Tsukahara tried everything he could to get the truth out of Senba. And I’m guessing he did, in the end, though he didn’t feel the need to make that public. Instead, all he wanted to do was fulfill an old man’s dying wish to see the daughter he’d traded his life to save.”
Yukawa spoke evenly and calmly, giving each word time to make an impact. Narumi remembered when her eyes met Tsukahara’s at the hearing, finally understanding that gentle look he had given her.
“I don’t think what Tsukahara was trying to do was a bad thing. But it was dangerous. Like trying to open a set of doors on the bottom of the sea. You don’t know what’s going to happen when you do. That’s why no one touches them. And when someone comes along who does, others try to stop them.”
Narumi looked over at Yukawa. “Are you saying it wasn’t an accident?”
“You think it was?” Yukawa asked, giving her a cold look. “Really?”
“Of course,” she wanted to say, but she couldn’t make her lips form the words. Her mouth was bone dry.
Yukawa was looking back out at the horizon. “I didn’t want to say anything, to be honest. There were a number of things about what happened that bothered me right from the beginning, but I decided to ignore them. That is, until I realized if I didn’t take action, it would have a tremendous impact on someone’s life, through no fault of his own.”
Narumi looked at him, not understanding.
“Tsukahara’s death wasn’t an accident, it was murder,” he said, suddenly turning to face her. “And the murderer … was your cousin, Kyohei.”
For a second, everything around her went silent. Even the surface of the sea appeared still, completely frozen. Then, sound returned with a gentle lapping of waves. She felt a gust of wind blow between them. She stared at the physicist. What the hell is he saying? For a moment, she wondered if she had misheard.
“Of course,” Yukawa said, “he didn’t do it on purpose. He didn’t even understand the meaning of what he was doing at the time.”
“What did he do?” Narumi asked, her voice a whisper.
Yukawa looked down in silence for a moment before turning to face her. “I believe I mentioned that the police were having a hard time re-creating the conditions for what happened. There’s a simple reason: your father is lying to them. In order to reproduce what happened, one very important condition needs to be met. It’s nothing elaborate, nor particularly difficult. But it’s impossible if you have a bad leg like your father, which is why forensics hasn’t even considered the possibility.”
Narumi flinched. “I don’t understand.”
Yukawa took a deep breath. “It’s simple. All you have to do is cover the top of the chimney, which causes the exhaust to flow back down the pipe, eventually resulting in an incomplete burn in the boiler. The carbon monoxide then goes up, and leaks out through the cracks in the pipe into the Ocean Room. I calculated that it would take fewer than ten minutes to reach lethal concentrations.”
“When did you know this?”
“I understood the potential when forensics first came to the Green Rock Inn and began sniffing around your kitchen burners.”
“But you didn’t say anything.”
“Like I said, I didn’t feel it was my place to get involved.”
“What changed your mind?”
“Something Kyohei said. He was watching one of the forensics officers come down the fire escape, and he mentioned there was a chimney up on top of the roof. That surprised me, because you can’t see the chimney at all from the ground, so he must have gone up there at some point. It’s unlikely to have been the last time he came to the Green Rock Inn, because he would’ve been much smaller, and it would’ve been too dangerous. That left the night of the fireworks. From there, it was a process of connecting the dots until I realized Kyohei must have done something—unknowingly, mind you—to the chimney that caused the accident.”
“Did you ask him?” Narumi asked.
“No, I didn’t want to lead him to the same conclusions I’d reached, not before he was ready.” Yukawa smiled. “Although I did have him help me a little. He stole the master key for me.”
“Why did you need that?”
“To investigate the Ocean Room. I realized the chimney must pass through the wall in that room, and that was the only door on the floor that was locked. Nothing raises suspicion like a locked door. As I thought, I found cracks in the back wall of the closet. That’s when Kyohei supplied the final piece to the puzzle—when he told me he’d gone around the inn before setting off fireworks and had covered up every place and window a bottle rocket might accidentally fly into. That’s when I realized why he’d gone up to the chimney.”
“He covered it?”
“A slightly dampened cardboard box placed over the top would do the trick. I’m sure those were his instructions.”
“My father’s instructions,” Narumi said.
Yukawa didn’t answer. Instead he picked up a small pebble by his foot.
“It wasn’t difficult to get Tsukahara to sleep in the Ocean Room. Your uncle could have given him some excuse for why they needed to switch rooms, then moved his things back into the Rainbow Room afterward. The sleeping pill could’ve been mixed into his drink.”
Narumi felt the last shreds of her hope fade as a deep despair settled in. It was impossible to imagine it having been an accident after hearing Yukawa’s theory.
“I can’t say how serious your father was about killing him, of course,” he continued. “He couldn’t have been certain that covering the chimney would have the desired result. No, I’d say he was just crossing his fingers—but intent is still intent, which suggests a motive. Which is why I had my detective friend in Tokyo investigate your family.” Yukawa stood and tossed the small pebble in his hand into the water. “Once we started down that road, it quickly became clear that we’d have to uncover what happened sixteen years ago. Thus my meeting with Mr. Senba. Who, by the way, didn’t confirm a thing.”
Narumi noticed she was trembling, and not from the cold. The sun today was bright and strong. Her wetsuit had completely dried out some time ago.
“Are you going to tell the police?” she asked with a shiver.
Yukawa’s lips settled into a straight line, and he shook his head. “I can’t, which bothers me. In order to prove your father’s intent, I would have to tell them what Kyohei did. I don’t think he would be punished, of course. But he would have to make a very difficult choice. He would wonder whether he should tell the truth. In fact, I think he’s already wondering. I think he knows the meaning of what he did by now.”