Isaac stopped for a split second before continuing to study, his eyes remaining on the same line for a moment longer than necessary.
"I don’t know," he answered, turning the page as though the question had not affected him at all.
"You do remember I have spatial sense, correct? I sensed you stiffening just now," Celia said with a pout, still leaning against his back without any intention of moving.
"I was surprised to hear what you said. That’s it," Isaac replied, keeping his attention on the book.
Celia turned around and wrapped her arms around his neck, bringing her face close to his ear.
"I’ll do something very nice for you if you tell me what is happening," she whispered, clearly expecting that the offer would be enough to make him talk.
"Uh-huh," Isaac nodded, acting as though her words had gone in one ear and out the other. He calmly moved his finger down the page and continued reading.
Celia stared at him for several seconds before narrowing her eyes. She had known Isaac long enough to recognize when he was deliberately ignoring her, and his current behavior was making her even more curious than his initial reaction had.
"What are you reading now?" she asked.
"A Chapter about spatial mathematics," he said.
"That sounds boring."
"It is."
"Then tell me what happened earlier."
Isaac turned another page. "I’m studying."
Celia made an annoyed sound but did not move away. Isaac knew that once she became curious about something, she would keep asking until she either received an answer or discovered it herself, and Celia was especially persistent when she had nothing else to occupy her attention.
She was also not someone who could sit quietly for long. Their current journey through the spatial domain had forced everyone to follow certain restrictions, and since they were not allowed to use their abilities during the trip, Celia had quickly run out of things to do.
As a result, she spent some time wandering around, talking to whoever happened to be nearby, and eventually returning to Isaac upon getting bored. She was settled beside him while he studied, which at least meant she was useful whenever he encountered something he did not understand.
"You are stuck on that part again," Celia said, pointing at the page over his shoulder.
Isaac glanced at the section she indicated. "I understand the first half. I don’t understand why they changed the reference point here."
"Because the original reference point becomes useless after the spatial shift. Look at the previous example. They already established that the coordinates move with the domain, so you have to adjust the calculation instead of treating the second position as independent," Celia explained.
Isaac looked back at the example and slowly worked through it again. After a few moments, the problem finally made sense.
"That actually helps."
"Of course it does. I finished university already," Celia said, sounding rather pleased with herself.
Isaac nodded. They kept studying, and time passed.
Before long, the door opened and Selene entered carrying a tray. The smell reached them before she had even crossed the room, and Celia immediately straightened up and looked toward the food.
"I brought some snacks," Selene said as she placed the tray on the table.
Celia picked one up before Isaac could reach for it. She took a bite, chewed for a moment, and then her expression brightened.
"These are really good," Celia said.
Isaac took one as well and tasted it. The outside was slightly crisp while the inside was soft, and there was enough seasoning to give it flavor without overpowering the rest of the dish.
"They are good," he admitted.
Selene smiled. "If you both like them, I can make them later. I got the recipe from Althea. We will just have to buy a few ingredients because I didn’t have everything the recipe called for."
"Then we should buy them. I want these again," Celia said immediately, licking her lips, eyeing the piece in Isaac’s hand.
"Althea made these?" Isaac asked while moving his piece away before Celia took it.
"Yes. Honestly, I was surprised to see a princess working in the kitchen," Selene chuckled.
"Apparently she has been hiding useful skills from us." Celia picked up another snack, pouting Isaac did not let her eat the one in his hand.
Isaac did not comment, though he found the idea amusing. He took another piece from the tray and returned to his book while Celia continued eating, which was probably the first time in a while that she had stopped asking questions without being told to.
By evening, Isaac had finished the topic he wanted to complete and decided to head downstairs for training. He followed the directions Alice sent him in the message. He had expected the lower floor to contain storage rooms or some other unused space, but when he opened the door leading to the basement, he found an enormous training room stretching far beyond what he had expected.
The room was illuminated by artificial lights built into the ceiling, and the walls and floor had clearly been reinforced to withstand heavy combat. There were several training areas, weapon racks, and equipment scattered around the edges, while the center had been left completely open.
Alice and the Sword Empress were already there.
Alice was in the middle of exchanging blows with the Sword Empress when she noticed Isaac entering. She stepped back and wiped the sweat from her forehead before looking toward him.
"You’ve been training since afternoon?" Isaac asked.
"Yes. I had free time so I decided to use it," Alice said.
Alice’s expression remained neutral, but her eyes were filled with anticipation. Isaac could tell that she was excited, even though she was making an obvious effort not to show it.
"You should join the training," she said.
"Are you sure? What if you just get beaten by me like always?" Isaac teased, walking toward the equipment rack.
"I have been training a lot lately. Unlike you, I haven’t been buried in work every day, so I’ve had plenty of time to improve. I think I can defeat you now," Alice replied.
Isaac picked up a pair of training bracelets and fastened them around his wrists. Once activated, they immediately reduced his physical stats, bringing his strength and speed down to a level suitable for training.
He flexed his fingers once and looked toward Alice.
"Are you sure one of my clones wasn’t training while I was busy?" he asked.
Alice’s eyes twitched slightly.
She didn’t reply, and stepped into the center of the room. The Sword Empress moved farther away and folded her arms, giving them space.
Isaac followed her and settled into his stance. The moment he raised his hands, Alice disappeared from where she had been standing and rushed toward him.
Her first strike came directly at his chest.
Isaac blocked it, but the force pushed him several steps backward. Before he could completely regain his footing, Alice followed with another attack, then another, keeping the pressure on him instead of giving him an opportunity to counter.
Isaac’s expression changed slightly.
She really had improved.
He shifted his stance and avoided her next punch by a narrow margin. Alice immediately turned and swept her leg toward him, forcing him to jump over it before she used the opening to drive another strike toward his side.
Isaac caught her wrist.
Alice reacted quickly and twisted her arm, using the movement to pull herself closer before striking with her free hand. Isaac tilted his head aside, felt the attack pass by his cheek, and released her wrist as he stepped away.
Alice landed several meters away and looked at him.
"You’re still holding back," she said with a frown.
"I’m wearing training restraints," Isaac said with a smile.
"That isn’t what I meant," Alice replied, her brows creasing more.
She likely knew Isaac was trying to get under her skin. But she still wouldn’t like him holding back. With their stats and skill sealed, she wanted a fair competition where both used all of their techniques and combat mastery.
However, Isaac holding back meant he was taking her as an easy opponent.
Isaac laughed quietly, seeing her getting angry. If this was the academy days, Isaac would be going home with a swollen eye today.
"Then I suppose I’ll have to take you more seriously," he said.
Alice’s eyes brightened.
She charged again.
This time, Isaac met her halfway, and the two collided in the center of the training room. Their movements became faster as Alice pushed herself harder, while Isaac gradually increased his own pace to match her.
The fight continued for several more minutes, with Alice steadily changing her approach as she tried to find an opening. Isaac adapted to her movements. A smile appeared on his face as he enjoyed the battle with her.
Eventually, Alice stepped back and lowered her hands. "Let’s stop for a moment. I need to catch my breath."
Isaac relaxed his stance and nodded. "You’ve improved quite a bit."
Alice took a few breaths before looking at him. "You too."
"Of course. It is me. So I obviously improved. I’m just that good," Isaac joked.
She clicked her tongue at his narcissist comment, but there was also a small smile in her eyes. Even if the fight had been a drawn, she seemed satisfied with how much better she had become.
Isaac removed the training bracelets and rolled his shoulders before glancing toward the side of the room. Someone was standing there.
Althea.
She was wearing training equipment rather than her usual clothes, with snug white pants, a fitted upper armor held in place by several straps, and a rapier hanging at her side. The outfit suited her well, and she looked far more like a trained swordswoman than the princess Isaac was accustomed to seeing.
"It’s time for my training. Since you all are here, how about we train together?" Althea asked calmly.
Her voice remained composed, but Isaac could tell she was excited. More importantly, she seemed to be hoping that both of them would agree.