That day, a heavy rain was falling.

Mid-May had arrived, and the rainy season had begun to blanket the Japanese archipelago.

“Good morning.”

Lightly wiping her hair with a handkerchief, Kaminari Nene stepped into the classroom, where a strange atmosphere hung in the air.

She walked over to the seat of Minaki Suzu, who had arrived earlier, and asked in a hushed voice.

“D-did something happen?”

“Toudou’s data was updated.”

Suzu’s emotionless, flat reply sent a chill through her chest.

She took out her smartphone and accessed the boys’ data on the school site.

“……”

The pairing count for Toudou Mizuki had increased to three.

She thought carefully about what that meant.

And little by little, she came to terms with the fact that she hadn’t been chosen.

Nene slowly swept her gaze across the classroom.

There wasn’t a single red ring, the proof of a pairing, to be seen anywhere.

Just then, the classroom door opened.

“Good morning.”

Houjou Noa entered, surrounded by her followers.

On her finger was something gleaming red.

As if to show it off, Noa brushed her hair back with her right hand, then smiled at Nene.

“Hello, Kaminari-san. I’m sure you already know, but since we’re in the same colony, I hope we can get along from here on out.”

A group of girls who had received a pairing from the same boy was called a colony.

As long as they were connected through the same boy, there was no way they could remain unrelated.

“…Pleased to meet you.”

Nene knew all too well, through countless rumors, just how troublesome and complicated relationships within a colony could be.

On top of that, the other party was the eldest daughter of the Houjou family, one of the Eighteen Founding Houses, while Nene herself was an ordinary commoner with no backing whatsoever.

Of course, once you became involved with a boy, colony-related issues were unavoidable, and she had thought she was prepared for that.

Even so, once she actually found herself in it, her feelings were complicated.

“Ah, you don’t need to worry about my position. You don’t have to be so polite. Let’s do our best to support Mizuki-kun together, shall we?”

Houjou Noa said this with an affable smile.

With her princely manner, she appeared at first glance to have no hidden side at all.

How much of it was sincere, Nene couldn’t tell.

“…Yes.”

As Nene replied with a stiff expression, Mizuki appeared from behind Noa.

“Good morning, everyone.”

“Mizuki-kun!”

Just as Nene changed her expression and was about to rush over, Noa moved ahead of her and approached Mizuki first.

“Hey, good morning. You’re soaked.”

“Hm? This much is fine.”

Noa took out a towel and wiped Mizuki’s hair.

Mizuki didn’t seem to dislike it at all, simply letting her do as she pleased.

“……”

Unable to do anything but watch their unusually close interaction from the side, Nene quietly returned to her seat.

She thought that Mizuki would come sit next to her soon anyway.

“Here, aren’t you cold?”

With a completely natural motion, Noa began to hold Mizuki close.

Before long, the classroom fell silent.

Even as all eyes in the room turned toward her, Noa remained calm, smiling pleasantly.

“Is everyone here?”

The homeroom teacher entered the classroom.

Only then did Noa finally let go of Mizuki.

“……”

A dull pain welled up deep in her chest.

The advantage she had held, being the only one among her classmates chosen as a pairing, was gone.

Kaminari Nene was no longer someone special.

◇◆◇

“First, an announcement regarding the special program.”

At the homeroom teacher’s words, the atmosphere in the classroom instantly grew tense.

Mizuki watched the teacher’s expression carefully.

“Normally, this is the time of year when the Party provides information about the special program, but it seems there will be no announcement this year.”

At those puzzling words, murmurs spread through the classroom.

At this high school, in addition to the Seikadan, students were traditionally required to take part in a special program, which was used to assess their suitability as Party members.

“For the first semester, a simple recreational activity will be conducted, so there is no specific assignment, or so I have been told by the officer in charge.”

“What kind of recreational activity are we talking about?”

“I have not been given any details, so I cannot answer.”

In response to Minaki Suzu’s question, the teacher shook her head.

An unpleasant silence spread throughout the classroom.

“Now then, moving on to the end-of-semester exams.”

As if nothing unusual had happened, the teacher continued speaking in a calm, matter-of-fact tone.

“This school is widely known as the first to introduce a class hierarchy system. However, for first-year students, Class K reached capacity in just three days, and we have received many complaints that the class selection rights, which form the core of the class hierarchy system, are not functioning properly.”

At that, the homeroom teacher swept her gaze across the classroom.

“The capacity of forty-six students per class is a standard set by the School Education Act enacted after the war. Since it is based on carbon dioxide concentration and is supported by a clear rational basis, the school cannot change this capacity on its own.”

Nene had heard the reason for the capacity from Noa before.

If it was grounded in law, then there was likely nothing the school itself could do.

“Therefore, starting with the upcoming end-of-semester exams, the board of directors and the student council have approved the introduction of a trade system, limited to first-year students.”

A trade system.

At the sound of those words, students instinctively exchanged looks with those around them.

“In the end-of-semester exams, the top five first-year students by academic performance will be granted trade rights in place of class selection rights. If any of those students choose to use that right to move into Class K, a trade will be conducted by swapping them with the lowest-ranking student in Class K.”

The murmuring in the classroom grew louder.

Kurosaki Ren, who had been silently observing, asked in a low voice.

“There might be a top-ranking student who doesn’t want to move, right? What happens in that case?”

“Of course, if that happens, no trade will take place. Trade rights are a right, nothing more. However, their validity period will be one month.”

As if she could no longer hold it in, Amagi Kuon stood up.

“Then what happens if someone from Class K ends up among the top-ranking students?”

“Since there is no class below Class K, they would normally be unable to exercise their class selection rights. However, as a special exception this time, we will permit them to transfer to any higher-ranking class they choose. Of course, if they have no desired destination, they are not required to exercise that right.”

“…I see.”

As Kuon sat back down, Noa spoke up next.

“What about those who already have a pairing? If they were separated from their colony, that could lead to a serious incident, couldn’t it?”

“Of course, students who already have a pairing cannot be sent to another class.”

“Then that means Kaminari-san and I are excluded from being trade candidates.”

With that, Noa cast a meaningful glance toward Mizuki.

At the same time, Nene beside him showed an unmistakable look of relief.

“I’ll repeat this once more. This is nothing more than a special measure intended to correct the current situation in which class selection rights are not functioning properly. We do not know whether a similar measure will be implemented in the second semester, nor has it been decided whether an entirely different approach may be considered. Once something has been decided by the board of directors or the student council, we will inform you again.”

After saying that, the homeroom teacher left the classroom without changing her expression.

The classroom fell quiet as if a lesson were in progress, with only the sound of slanting rain striking the windows echoing through the room.