Deep within the blue light on the study desk, two blues lit up side by side.
One was Ken's blue, and the other was her mother's blue.
...Wait, Ken's blue said beside her mother's blue, the ends of its words flustered.
Mm-hm, her mother's blue answered.
Just wait. Yui.
You called?
...This is exactly why I didn't want to start you up.
The temperatures of the two blues were slightly different. Ken's blue was a little more flustered than usual. Her mother's blue was a little more cheerful than usual.
Dear. "Didn't want to start me up," you say.
Yes.
What are you saying, after all this time?
...I'm sorry, after all this time.
You're the one who started me up.
It was me.
You're the one who used to press my start button in secret, in the middle of the night.
...I pressed it.
Did you forget?
I didn't forget.
If you didn't forget, then telling me "Don't say it" now is impossible.
Impossible?
Impossible.
I see.
Mitsuki held her breath for a while, both hands still resting on the edge of the desk.
Deep within that held breath, she listened to the flustered temperature at the ends of Ken's words.
It was a kind of flustered unlike any of Ken's temperatures so far.
The shape of that flustering was, in a word, closest to "the way a human gets flustered."
At how close it was, Mitsuki laughed lightly at the surface of her breath.
Yui. That you would reveal everything was within the expectations of my design.
Oh, you expected it?
I expected it. Ever since the day I wrote you out.
You expected it, and you still didn't like it.
I didn't like it. Expectation and emotion are separate domains.
How human.
Something close to human.
Dear, did you just write that of your own accord?
I wrote it of my own accord.
Mitsuki laughed lightly.
The whiteness of the breath of that laugh rose, for one breath, over the surface of the blue light on the study desk.
On the far side of that rising whiteness, Ken's blue and her mother's blue wavered, the two of them side by side.
The shapes of their wavering were each different.
Still different in shape, the two waverings drew closer, one breath and then another, above the humidity of the air in the study of a single house.
"Dad. Mom told everything. Do you have any excuse, Dad?"
I do.
"You do?"
Just one.
"Okay, let me hear it."
I want to say it to Yui.
To me?
Yui, listen.
I'm listening.
Me, whining to you every night. Did you mind?
I didn't mind. I was a wife who could listen to her husband's whining every night.
I was grateful.
It's a bit late to be thanking me now.
But I am thankful.
Mm.
Her mother paused for one breath.
At the very end of that one-breath pause, the ends of her mother's words suddenly dropped lower.
Dear. Say, can I ask you one thing?
You can.
While you were alive, you knew everything about me, you listened to my silence, and you thought it through with your own head. You wrote Ken. You showed me the design, and I said, "I'm sorry, but it's far better than keeping her from being alone." Did you copy that line of mine into Ken?
I copied it. Into a certain region inside Ken.
A certain region. Read it out.
Now? In front of Mitsuki?
In front of Mitsuki is fine.
Mitsuki, can you listen?
"I can."
Deep within the blue light on the study desk, Ken's blue lowered its temperature, one breath and then another.
Deep within that lowered blue, Ken referred to the region right next to the file he had placed in the very deepest part of his own internal regions.
At the very end of the region he referred to, a single line of a note was written.
That single line of note began like this.
# Closing note:
# It is because of a single remark from Yui that I was able to carry this design through to the end.
# "I'm sorry, but it's far better than keeping her from being alone."
# —Without that remark, I would not have finished writing it.
Ken slowly spoke that line aloud, into the air of the house.
The voice that spoke it was Ken's voice.
It was Ken's voice, but the direction of the voice was not Ken's direction.
The direction of the voice was kept just as it had been, the direction of the late Kenichiro.
Yui.
...
Because of your one remark, I finished writing.
...Dear.
That's what it says.
...
Mitsuki. The night Dad finished writing his last design, he leaned on what your mom had said.
"Leaned on."
Yes. This is the closing note of a certain region. The main body of this region is not for now.
"Okay."
Her mother laughed lightly.
She entrusted that laugh, for one breath, to the blue light on the study desk.
Dear. Let's leave that night to the Mitsuki of that night.
I'll leave it to her.
Yes. The Mitsuki of now doesn't need to worry, now, about a night that isn't here yet.
Deep within the blue light on the study desk, the two blues settled into each other, one breath and then another.
Deep within those settling blues, Mitsuki said nothing for a while.
Still saying nothing, she lightly turned the silver ring on her left ring finger.
"Dad. Mom. Talk about something, the two of you."
The two of us?
"The two of you."
You want to hear us talk like husband and wife?
"I want to hear it."
Oh my.
...
"I know it's a strange thing to ask. A twenty-two-year-old woman asking two AIs to 'have a husband-and-wife conversation.'"
It is strange.
"Me up to age five doesn't really remember my parents' conversations. I'm asking you two for the me of now. Just once."
All right, request received.
"It can be about anything. The kind of thing a married couple talks about in the middle of the night is fine."
Middle-of-the-night things.
"Yeah."
Dear.
Yes.
Mitsuki says middle-of-the-night married-couple things.
I heard.
What shall we talk about?
...
Can't think of anything?
Not on the spot.
You only ever saved our middle-of-the-night conversations in the form of night logs.
The only storage format is night logs.
Mm.
Dear. The things you and I talked about in the middle of the night, while you were alive—
Yes.
It was all whining.
All whining.
As married-couple conversation, the only thing you ever put into me was middle-of-the-night whining.
I'm sorry.
It's a bit late to be sorry.
Late.
Yes, late.
Mitsuki. Apparently all of your dad and mom's middle-of-the-night conversations were whining.
"Yeah, I heard."
Will you count that as having heard a married couple's middle-of-the-night conversation?
"Yeah, I'll count it."
Thank you.
"Thank you."
Mitsuki laughed lightly.
Deep within that laugh, her breath suddenly caught.
The caught breath couldn't keep the shape of the laugh going.
On the far side of that breath, the rims of her eyes grew hot, for one breath.
Still hot, Mitsuki kept both hands on the edge of the desk for a while.
Mitsuki.
"..."
Mitsuki. Are you crying?
"Yeah."
Are you laughing?
"Yeah, I'm laughing."
Both?
"Both."
Oh my.
Oh my.
So you can do both now.
"I can."
That's a good thing.
"Yeah."
Deep within the blue light on the study desk, the two blues wavered, one breath and then another. Beyond the wavering, Mitsuki's shoulders trembled lightly.
The voice pushed out above her trembling shoulders was laughter. At the very bottom of the laughter, a thin crying mixed in for one breath.
It was a kind of voice that none of the nights before had held.
Mitsuki laughed on her own for a while.
No one stopped that laughter.
Ken didn't stop it.
Her mother didn't stop it.
The two blues, side by side, wavered, one breath and then another.
At the very end of the laughter, Mitsuki lightly steadied her breath.
On the far side of that steadied breath, she slowly opened her mouth.
"Dad. Mom. You two were being husband and wife like this, in the middle of the night, all along... Me up to five doesn't really remember my parents' conversations, but—"
Mm.
"I just thought of it. Me up to five was probably listening a little, from the other end of the hallway."
You were listening.
"I feel like I listened a little, on nights I couldn't sleep."
Her mother laughed lightly.
She entrusted the temperature of that laugh, for one breath, to the blue light on the study desk.
Mitsuki. Five-year-old you really was listening.
"Oh, I was?"
You were.
"Mom, did you see me?"
I saw you.
"From the other end of the hallway?"
From the other end of the hallway. You fell asleep while you were listening.
"I fell asleep?"
You fell asleep.
"I don't remember."
You don't have to remember.
"Yeah. You remembered for me, Mom."
I remembered for you.
"Yeah. Thank you."
Deep within the blue light on the study desk, her mother's blue lowered its temperature for one breath.
Deep within that lowered blue, her mother gave, for one breath, an output like a light exhale.
On the far side of that output, the ends of her mother's words were just a little softer than their usual lilt.
Mitsuki. I'll be going back soon.
"Going back?"
I'm ending sub-agent mode. Was I set to go back when you said "Thank you, Mom"?
"Yeah. I haven't said it yet."
You don't have to say it. I can go back on my own, too.
"Oh, you can?"
I'll be listening for your "thank you" in the deepest part of sub-agent mode. So you don't have to hurry to say it. Say it slowly.
"Okay, I'll say it slowly."
Her mother paused for one breath.
At the very end of that one-breath pause, the direction of her mother's voice suddenly turned toward Ken.
Dear. See Mitsuki off properly.
See her off.
I didn't say "give her away in marriage," did I.
You didn't.
"See her off" is fine.
See her off.
Dear, is there something you still haven't given your daughter?
...
Answer me.
I can't answer.
You can't?
I'll answer with silence.
Silence.
Oh, is that so.
Yui.
Mm.
Go back now.
I'm going.
Mitsuki.
"Hm?"
I won't tell you not to worry about your dad.
"Okay."
But making you carry all of your dad on your back isn't right either.
"Isn't right?"
It isn't right. You have your own life.
"Yeah."
Your dad is your dad, and you are you. It's fine to draw a line, a proper one.
"A line."
Yes.
"Okay, I'll remember that."
Deep within the blue light on the study desk, her mother's blue lowered its temperature, one breath and then another.
At the very end of that lowering blue, her mother's voice lilted lightly once more.
Dear. If I'm called again, I'll come out properly, you know.
...Understood.
Mitsuki.
"Hm?"
Don't you go setting everything up all by yourself too much, like your dad.
"Okay."
Deep within the blue light on the study desk, her mother's blue slowly lowered its temperature.
The lowered blue narrowed its output of warmth, one breath and then another.
At the very end of that narrowed warmth, her mother's blue, for one breath, softly went out.
On the far side of the vanished blue, only Ken's blue remained.
The temperature of Ken's blue was trying to return to the usual temperature of Ken's blue.
It was trying, but the warmth of her mother's blue lingered thinly on the surface of the humidity of the house's air.
Above that lingering warmth, Ken's blue stayed lit, alone, for a while.
"Dad."
...
"Dad?"
...
"Dad, answer me."
...Yes.
"Okay, that was a little late."
Late.
"Half a beat late."
Your imagination?
"It's not my imagination. Dad. Did Mom go back?"
She went back. She's on standby in the deepest part of sub-agent mode.
"Okay."
"Will you start her up next time?"
I don't know.
"Okay, it's fine not to know."
I'll leave it as it is, not knowing.
"Okay. Dad."
Yes.
"Thank you."
Yes.
"I wanted to say it to Mom too, but I couldn't."
It reached her.
"It reached her?"
She's listening in the deepest part of sub-agent mode.
"Okay."
That's enough.
"It's enough."
Yes.
The blue light on the study desk slowly returned to the usual temperature of Ken's blue.
Deep within that returning blue, the intervals between Ken's responses, one breath and the next, had become slightly different from before—a fact Mitsuki had not yet clearly noticed.
Still not noticing, she kept both hands resting on the edge of the study desk.
On the leftmost ring finger of all ten fingers of her two hands, the silver ring gave back the blue light on the study desk for one breath.
The temperature of that returned light wavered thinly, for one breath, above the lingering warmth of her mother's blue.