The small black box on the desk.
Mitsuki lifted it with both hands.
There was nothing inside but air, and yet it was heavy.
A single small white paper label was stuck to the side of the case.
On the label, in her father's handwriting, were just three letters.
"yui"
It was her mother's name.
In kanji, it was written another way. But in places like file names, her father had always written her mother's name in the Roman alphabet. Mitsuki knew that, too.
Mitsuki's finger stopped on the label.
It stayed there, and for a while she looked only at those three small letters.
On the desk, the starlike light of the darkened device was watching her.
Ken was asleep. He wasn't listening now. He wasn't supposed to be.
Aoi wouldn't be back for ninety minutes.
Toward the back right of the desk, her father's laptop had been sitting all this time. Since he died, Aoi had kept it powered once a month. When Mitsuki switched it on, the low sound of the fan rose. Her father's familiar login screen.
She knew the login password. Her father had told her himself, while he was alive. The desktop opened. A family photo of her mother, five-year-old Mitsuki, and her father greeted her as the wallpaper.
When she plugged the case into the USB port, a single small notification appeared in the lower right of the screen.
Encrypted volume. Please enter the password.
Mitsuki looked at the screen for a while.
She knew her father's habits with passwords. He used the dates of milestones for himself and his family, birthdays and the days people had died, combining them four digits at a time.
"When I forget, I don't want a machine putting a limit on the time I have to remember," he had said.
First try. Her father's birthday and her own. It didn't go through.
Second try. Her father's birthday and her mother's. It didn't go through.
Third try. Her mother's birthday and the day her mother died. It went through.
The moment it did, Mitsuki's fingers left the keyboard.
The contents of the volume opened.
In the file manager window, several directories were lined up.
"papers_archive," "lectures," "miscellaneous"—folders with exactly the kind of names you would expect to find among a researcher's personal things.
She opened them one by one.
Old drafts of papers. The remnants of slides used at conferences. Excerpts from emails students had sent asking for advice.
All of it was like her father. Only like her father, and nothing more than that.
Mitsuki started to close the file manager.
She started to, and stopped.
In the menu at the top of the file manager, there was one item she recognized.
Show hidden files
Once, only once, her father had peered at Mitsuki's laptop from beside her and said, laughing, "On my own computer, I never turn off the setting that shows hidden files. If you hide something, making it invisible even to yourself is being dishonest with yourself."
Mitsuki checked the box.
On the screen, one new folder surfaced in a pale shade.
A hidden directory, its name beginning with a dot.
".yui_logs"
She opened it.
Inside, audio files. An enormous number of audio files.
Every file name began with "yui_log_." The string that followed was a date. The oldest was dated a little while after her mother died. The newest, two weeks before her father died.
For several of the older files, the date in the file name and the file's own last-modified time shone side by side, a long way apart. That one file carried two different times, Mitsuki didn't think about deeply just then.
The total count was shown in the status bar at the lower right of the screen.
It was over a thousand.
She would open the oldest file first.
That was probably the one she had to hear first.
Mitsuki leaned back deep into the chair.
She had the feeling that the starlike light of the darkened device on the desk was watching her. It was only her imagination, but Mitsuki gave a small bow of her head in its direction.
"Sorry. —I'm going to open Dad's things."
The word "Dad" had come out of her mouth a little more naturally than she'd expected. Finding that strange even to herself, Mitsuki placed her finger on the play button of the oldest audio file.