The housekeeper who had undergone plastic surgery to impersonate the old lady of the castle was named Mutsumi Nishikawa.
When the gardener heard the name, his face clouded with regret. In his memory, she had simply vanished one day not long after being hired.
Hayashi Yoshiki felt a subtle joy upon learning the name.
Before dinner, he had already solved the mystery of the castle.
"What, you've already solved it!?"
The old lady in the wheelchair suddenly became unusually animated. She rolled herself over energetically, eyes glittering with anticipation.
"Yes, it's the puzzle involving the chessboard in the garden, right? Honestly, it wasn't that difficult."
"As expected of a Tokyo detective! So where's the treasure? Tell me the secret already!"
"Please, don't get too worked up."
Hayashi Yoshiki smiled gently in the face of her eagerness.
"Mother… I understand how excited you must be, but with your health, it's better to stay calm," Mamiya Mitsuru added with a wry smile.
"Don't tell me not to be excited! This is my husband's legacy! Of course I'll take it seriously!"
The old woman glared fiercely at Mamiya Mitsuru.
"Or are you planning to steal my husband's treasure when I'm not looking!?"
Mamiya looked helpless.
Though he was indeed curious about the so-called treasure, he had no intention of snatching it. The current fortune of the Mamiya family was more than enough for him.
But Mutsumi Nishikawa didn't believe that for a second.
She had killed multiple people and altered her face into a monstrous mask. Now that the treasure was within reach, she would never let anyone else claim it.
"So, what's the solution to the puzzle!? Tell me now!"
"Well... there's still about half an hour left."
Hayashi Yoshiki glanced at his watch and smiled.
"Please wait a little longer, and I'll reveal everything."
Seeing Hayashi Yoshiki's calm expression only made Nishikawa Mutsumi more suspicious.
Why wait half an hour?Is he stalling for time so he and Mamiya can steal the treasure?
Judging others by her own ruthlessness, she now saw everyone as a potential thief.
Hayashi Yoshiki said nothing further.
The old lady continued to urge him, refusing to let Mamiya Mitsuru leave the room. Half an hour passed in this tense silence… until footsteps echoed outside the room.
"Hayashi-kun, I heard you ran into a case. What happened?"
Inspector Megure entered with several police officers.
Both Mamiya Mitsuru and Nishikawa Mutsumi froze in confusion. Behind the police, the gardener appeared, bowing apologetically.
"I'm sorry, Madam, Master… They said they were investigating a criminal case, I couldn't stop them."
"Apologies, Mr. Mamiya. While solving the puzzle, I uncovered another case and decided to call the police myself."
"Yes. The case of a housekeeper named Mutsumi Nishikawa who murdered and replaced the original lady of the house via plastic surgery, and then set fire to your wife years ago."
At that moment, Mutsumi Nishikawa's expression twisted in horror.
Even with a face surgically altered into bark-like wrinkles, she still managed to express shock and fear.
Hayashi Yoshiki casually pulled a file from his coat.
"I asked someone to help me investigate old plastic surgery records. Though it happened many years ago, the surgeon remembered clearly—after all, it's not every day a woman in her twenties pays to look like an old lady. It was the only time in his career."
"Nishikawa Mutsumi... I remember that name!"
The gardener's mouth hung open.
Inspector Megure, stunned, took the file and motioned for his men to move in.
"What do you think you're doing!? I don't know what he's talking about! Let me go!"
As soon as the officers approached, Mutsumi Nishikawa started to thrash violently.
But when Hayashi Yoshiki revealed the final proof—that the real old lady's corpse was hidden in the castle's secret passage—all resistance shattered.
What followed was sheer madness.
Despite her façade of frailty, she suddenly stood from the wheelchair and lunged at Hayashi Yoshiki, gripping his collar with claw-like hands.
"WHY! Why are you doing this to me just when I was about to get the treasure!? Where is it!? Tell me!!!"
"I'm afraid I can't do that."
Calmly, Hayashi Yoshiki looked down at her gnarled fingers and pried them away.
"At this point, the treasure belongs to Mr. Mamiya. I have no right to tell you."
"You bastard!! Tell me!!!"
Nishikawa Mutsumi lost control, screaming in hysterical rage.
After years of pretending to be disabled, killing, and waiting for the reward, how could it all go to a son-in-law she despised?
Inspector Megure and his men rushed forward to restrain her. Two officers handcuffed her and dragged her away, still shrieking.
Afterward, Hayashi Yoshiki showed Megure the entrance to the castle's hidden passage, where the real old lady's corpse was found.
As for the mystery of the chessboard?
It didn't lead to treasure but to a beautifully concealed garden landscape.
If Hayashi had revealed that to Mutsumi Nishikawa, she would have despaired at her entire plan amounting to nothing.
But instead, she was taken away thinking she'd lost a fortune—a different kind of despair.
Hayashi Yoshiki found that equally satisfying.
Standing quietly behind the scene, Hayashi Yoshiki took out his notebook and flipped to a designated page.
Mutsumi Nishikawa->Two days later, at 20:41:53 p.m., dies of a heart attack in the detention center.
Mutsumi Nishikawa->Four days later, at 20:41:53 p.m., dies of a heart attack in the detention center.
Two identical names. Two different dates.
When writing the two-day entry, Hayashi visualized her original face, before surgery.
When writing the four-day entry, he imagined her current, altered face.
Whichever night she dies on will reveal whether the Death Note distinguishes between facial identity—and whether plastic surgery breaks its connection.
Another puzzle piece, falling into place.