The Only Diamond in the World

Roina's face went white. She clenched the pendant at her throat until her knuckles blanched.

The magic meant to prevent pregnancy—had vanished.

House Amasto was one of the four families that served as pillars of the great Caelum Empire.

Few people remembered it now that peace had held for so long, but the house was also the foremost martial lineage ever raised from margrave to marquis for the merit of driving back the northern barbarians. Once, it had been better known for tearing coarse bread alongside its soldiers and coming home caked in dust.

Even the Amastos, after long years had passed since they subdued the barbarians, grew steadily richer on the trade that ran through the northeastern routes, until at last they became a distinguished house of old name. The great turning point had come when the emperor of that age threw his weight behind Amasto as a rising power meant to shove aside the established ducal families.

That emperor, making a lavish show of his generosity, had folded the vast and supposedly useless northeastern plateau into the margrave's domain. He had never imagined that such enormous profit could come flowing in from beyond a bleak highland where only scattered nomadic tribes lived.

In any case, that formidable House Amasto currently had, besides the son who would be its heir, one daughter treasured like gold and jade. That daughter was Mayli.

Tap-tap-tap-tap... tap-tap-tap...

Mayli sat in the office, reducing an innocent quill to ruin. Every time the nib met the stationery on the desk, it gave a light tap.

A boy reading on the sofa in one corner of the room lifted a brow, his face thick with irritation. He was blond, handsome enough, and looked as though he had only just stepped into his late teens.

"Ahem."

When he cleared his throat in pointed warning, Mayli glanced at him and paused. Then she glared at the paper as if she might fall straight into it, lifted the pen, and set it down on the sheet again.

Tap... tap-tap... tap-tap-tap-tap...

"Ah, come on!"

At the boy's shout, Mayli raised her head and met his eyes. Her brows were drawn up sharp; her temper was plainly foul.

"And where, exactly, did you leave your dignity?"

"That's my line! You barge in demanding I lend you the office, and then you sit there tormenting a pen—what is wrong with you?!"

Whether it was his ruined hour of reading that rankled him, the boy shouted with a full measure of irritation. Mayli did not so much as blink.

"Hmph. You're still too young. I could tell you and you wouldn't understand."

"What are you even saying? Get out of my room this instant, you witch!"

Joseph flared and lunged to snatch the quill. Mayli slipped easily past the sole heir of the great Marquis Amasto and hooked his ankle out from under him. The blond boy nearly went down, but he rolled and landed with nimble grace, then cried out in a wounded voice.

"Seriously, what is it?"

"Hah..."

"Sit there rolling a pen around all you like—what's going to come out of that rock you call a head? Stop wasting pen shafts and go in and sleep."

"Hey!"

Joseph had sneered with plenty of spirit, but the moment his words lit twin flames in Mayli's eyes, he ducked behind the sofa on reflex.

She might be playing the demure noble lady for now, but Mayli was a woman who had taken formal training with the knight order. She was far stronger than Joseph, a young nobleman who preferred books to swordplay.

It had followed naturally. Joseph had grown up taking his beatings from her.

"...Ugh, fine! If you're truly that stuck, I'll make a special exception and listen, just this once. I really am objectively smarter than you, after all."

It was true. While Mayli kept her distance from books and spent her days in the saddle—and through these last few years, while she suddenly played the gentle lady in hopes of becoming crown princess—Joseph stood on the verge of graduating first in his class from the Academy, having already entered it as its youngest top scholar.

Even so, Mayli shot her unreliable little brother one sidelong glance and tossed the words out as if they cost her nothing.

"It's because there really isn't anything I can say."

"...Is it about the imperial house?"

Mayli said nothing. Reading the silent yes, his face grew grave along with hers.

"Did the crown prince finally come to his senses and decide to strike a hellion like you from the ladies-in-waiting?"

"You—!"

Mayli seized his bangs at a speed he had no hope of dodging, and they scuffled for a moment. Once she had spent a little of her strength, she felt considerably better. Joseph, clutching a forehead gone red from a hard flick, did not appear to share the sentiment.

"To put it simply, I've been trying to work out how to rescue the grain of sand the Little Sun kidnapped."

"What. That's nothing. Give up on the grain of sand."

"Haa."

Mayli rubbed at her temple and spoke again.

"Except the thing I thought was a grain of sand turns out to be a raw diamond. The only one in the world—and so important that, without it, the world falls apart."

The light in the boy's eyes sank as he listened. He shook his head once more.

"Still no. It's too dangerous for you to move yourself. Diamond or world, you don't get to be the one who burns first."

"Haaa... Little brother, is there really no way? You're supposed to be a genius. If you're that scrawny and you can't even use your head, what good are you?"

"Oh, for—you haven't even explained the situation properly. How am I supposed to know? Whatever it is, if it's something you can't so much as mention, then don't move yourself. At least leave it to someone who has power."

Knock, knock.

Someone rapped at the door. Joseph, sitting askew on the sofa, shook out his hair and called, "Who is it?"

"Young master, the book you asked to borrow."

It was an old servant's voice. Joseph's expression eased a little. He went to the door himself, opened it, and took the book. Mayli watched the whole exchange with her chin propped on her hand.

"Yeah. Good work. Precise as ever."

Joseph lifted the book, fluttered through the pages, and gave the steward a perfunctory nod of thanks. If it was a volume the steward would bring in person, it was either precious or the only copy in existence. That was what Mayli thought.

From the moment the book was in his hands, Joseph's attention was oddly stolen by it. He looked itchy with the urge to read it at once. Curious what volume could do that to him, Mayli stole a glance at the cover—and the book had none.

Hm?

No. It had seemed to have no cover, and then, between one instant and the next, letters appeared upon it. Mayli stared at the book, blank.

"Ori... gin of the Star...?"

"Hm? What. You know this book? You need mana to read it."

Interest lit in Joseph's eyes. Mayli ignored him and asked.

"Hey. Do you know anything about the Archmage?"

"Ah, that's the subject I'm researching now. A great deal still hasn't been brought to light. Lately, you see, it's how the Archmage's use of mana interlocks with the vertically descending structure of ancient magic..."

"Enough of that. What about a case where there is already an Archmage, and another Archmage appears? Has that ever happened? Two Archmages at the same time. Not the sort of thing where one passes it on at the end of his life."

Joseph lifted a pair of inexplicable spectacles onto his face and answered.

"Mm. It has. Exactly once."

"Really?"

Color rushed into Mayli's face. She started to speak.

"The truth is, yesterday I—"

"Dead."

"......What?"

"The second Archmage, I mean. By the time they were found, they were already dead."

Mayli's pupils wavered. Joseph sighed.

"Sister. Don't. It really isn't that."

"What? And what do you think I'm trying to do?"

"I meant to honor your wishes and pretend I hadn't noticed. But the subject you just asked about was a little too blatant, wasn't it?"

Mayli pressed her mouth into a hard, flat line. The boyish youth let out another deep sigh.

"If a second Archmage has appeared, the imperial house will try to possess them no matter what, and the Archmage will try to take them away. A second Archmage. Getting involved in that is suicide."

"No."

"What do you mean, no—"

Joseph opened his mouth as if to launch into a speech, but the look on Mayli's face left him no choice but to close it. She was watching him with eyes burning with fierce resolve.

"What I'm going to do isn't getting involved."

Mayli shot to her feet and snatched up the sword that had been set in one corner of the office. She drew it with practiced ease and checked that the edge was properly honed.

Joseph laughed, hollow with disbelief.

"That's the signal she can't be talked down, isn't it...? Aigoo..."

He pressed a hand to his brow. He knew that temperament of hers—once it caught, she was a chariot no one could stop. It seemed he would have no choice but to help the only sister he had.

Roina waited with stubborn patience for the moment she would be left alone again in that luxurious prison called the crown prince's bedchamber. The brief span when Ethan stepped away. Just before the crown prince returned, Ethan went out in person to receive him. It was only about five minutes, but that was enough.

Roina hopped down from the sofa. The pendant at her throat swung, unsteady. With an uncomfortable look she gave the choker a tug. Inside this Imperial Palace, a dog collar like this was no different from a slave's brand, and she wanted nothing more than to throw the thing away.

Damn it...

For the contraceptive magic to vanish—at this rate, pregnancy was truly only a matter of time. Absolutely not. In a pregnant body, escape from this place would grow even more remote.

It was something she could recognize at once, because she had studied the shackle around her neck without rest. She knew, with certainty, that she had a talent for magic. That was why she had thought she needed to find the Archmage.

The man with the golden eyes.

That man was surely the Archmage she was looking for. Roina was firmly convinced of it.

As she drew toward the pillar, she glanced once more, in passing, at that same painting on the ceiling.