The morning dining car was quieter than usual. The sky over Belidot was clear, and beyond the window stretched the stone roofs of the academic city Rilkenote. It was a peaceful morning—as if last night's chaos had never happened. Kuraf turned her gaze toward Dan Hen across the table. Everything was the same as always. Silver hair reaching to his waist. Reddish-purple eyes. The habit of lining up his spoon. Nothing had changed. He was back to being male. Of course. Everyone had returned to normal last night. Dan Hen murmured "Yeah" while scooping up soup. The moment that low voice reached her ears—— Kuraf's ears flushed red. (Why now?! You had the same voice yesterday!!) She didn't understand it herself. She hurriedly tore off a piece of bread and stuffed it in her mouth. She couldn't taste anything. "[laughing] Huh? Everyone's back to normal, but Kuraf's the only one whose face is redder than yesterday?" Bronya said it with golden eyes sparkling. Purple hair with black mesh swayed in the morning light. He was clearly enjoying this. "[serious] A flushed complexion may indicate poor health." Natasha reached out to touch Kuraf's forehead with a serious expression. White-silver short hair and light blue eyes—completely earnest. "[angry] Both of you, shut up!!" Her voice cracked. She tried to slam the table, and the soup rippled. Bronya clutched his stomach, laughing "Ahahaha!" Natasha continued muttering "No, that's not the case, as a physician——" Only Dan Hen quietly turned his gaze out the window. The corner of his mouth rose—just barely, by a millimeter. Kuraf saw it. She stuffed more bread in her mouth. "[serious] More importantly, the Cradle." Dan Hen spoke without changing his tone. "[serious] Last night, the gem's light resonated with the underground ruins. We can enter the first layer with an exploration permit. I want to investigate it today." "[excited] I'm in! I was thinking yesterday too—those wall patterns might be connected to the gem!" Bronya started to stand. Natasha added, "Everyone's health is fine." Kuraf gripped the gem in her hand. It was round and slightly warm. (……Let's go.) --- The entrance to the Cradle—the underground ruins of Rilkenote, a pre-historic civilization structure spanning three layers and approximately 2 km²—was tucked away behind the Grand Library. When they bought a permit from the reception clerk, it cost 30 Lukes per person. "[sarcastic] 30 Lukes per person?! 120 Lukes for four people?! My wallet's already hurting from yesterday's detention facility incident!!" "[serious] It's a necessary expense." "[serious] That's right." "[serious] Split it evenly." "[sarcastic] Cold!! Three against one, that's cold!!" Bronya carefully counted out 30-Luke coins one by one from his wallet and handed them over. The clerk stood there dumbfounded. The four of them descended the stone steps together. Damp air drifted up. Instead of torches, old electric lamps lined the walls, casting thin orange light on the stone. The first layer was exploration-permit-only—the second layer and beyond were designated danger zones—so researchers could enter up to here. Bronya spread out copies of records from the library. Careful transcriptions of the gem's patterns. Holding them, he methodically illuminated each section of wall. "[serious] Not here. ……Not this either. Let's move to the next section." Natasha walked alongside him with the light. Kuraf and Dan Hen followed slightly behind, splitting up to examine the opposite wall. The stone was ancient, its surface densely carved with fine patterns. It was cold to the touch. Lines carved by someone thousands of years ago still remained here. Kuraf traced them with her finger, thinking about the gem. Where was this made? Who made it? "[excited] Found it!!" Bronya's voice echoed off the stone walls. All four gathered. Bronya held the copy against the wall and illuminated it with light. It was a perfect match. The fine star-chart-like patterns floating on the gem's surface were carved directly into this section of wall. The line thickness, the angles—everything was identical. "[serious] This gem was either made here—or at least, it was stored here." Bronya stated it with certainty. Not his usual light tone. His voice carried conviction. "[surprised] Really……it came from here." Kuraf took out the gem and brought it close to the patterns. It glowed softly. The wall's patterns began to shine in the same color as the gem. The surrounding stone vibrated faintly. The light spread along the lines——and a section of the wall slowly opened inward. A hidden passage. "[excited] Whoa——!!" Bronya and Natasha cried out simultaneously. In that instant, air trapped in the passage for years came rushing out all at once. Whoosh!! Dust scattered everywhere in a cloud. "[laughing] ——Ugh……ha……achoo!!!!!!!!" Bronya sneezed spectacularly. The echo bounced off the stone walls three times. "[serious] Are you alright!" Natasha rushed to rub his back. Bronya sneezed again. "O-okay……achoo!!" Kuraf and Dan Hen——were both peering into the passage. After a moment, Bronya looked up. "[sarcastic] ……Are we being left behind?" "[serious] ……It appears so." --- The passage led directly into the second layer zone. Dan Hen turned back. "[serious] The second layer and beyond are danger zones. Natasha and Bronya, wait at the entrance." "[sarcastic] Aw! I want to go too!" "[serious] If someone who can't stop sneezing from dust enters a narrow passage, it'll be a problem for everyone." "[sarcastic] That's too logical……!!" Natasha rubbed Bronya's back and said, "Let's wait here. I'll stay with you." At those words, his expression relaxed slightly. Only Kuraf and Dan Hen ventured deeper into the passage. The stone ceiling was low. If they walked side by side, their shoulders would almost touch. No torches—only the gem's light to guide them. That light hit the walls and flickered gently. After walking for a while, they emerged into a small chamber. Ancient characters were carved densely across the entire wall. "[serious] ……Here." Dan Hen pulled out the ancient language materials he'd obtained from the library. He turned pages, comparing them with the wall's text. Kuraf stood beside him, holding the light. Their shadows stretched across the stone floor in parallel. "[serious] ……I can read it." He said it quietly. Then, slowly, he began to speak the translation aloud. "[serious] 'This sphere responds to the most honest emotion the holder wishes to hide.'" Kuraf looked at the gem. "[serious] 'As long as the sphere is held while that emotion remains hidden——it will continue to change the forms of those around you. The moment the emotion is faced——a solution is given.'" "[serious] ……So that's what it was." "[serious] There's more." "[serious] 'However——the sphere's memory does not fade. The same will occur for whoever touches it next.'" Silence fell. In the stone chamber, only the gem glowed softly. "[serious] ……So it can't be disposed of. We can't let anyone else touch it." "[serious] You'll have to keep holding it." The words came back quietly. Not accusatory. Just stating fact. Kuraf gripped the gem tightly. In the cold stone room, only her palm was warm. She was silent for a while. Then——her mouth opened. "[sad] ……I'm sorry for the trouble." She said it. No excuses. No bravado. Not rushed. Dan Hen paused for a beat. "[serious] If I thought it was trouble, I wouldn't have come." He said only that, then headed toward the passage. His back receded into the distance. Kuraf couldn't move. The center of her chest grew warm. The same place as where the gem rested. (……Why does he say things like that so casually?) The gem in her hand seemed to glow just a little brighter. --- When they emerged above ground, the sky over Rilkenote was the blue of late morning. The four of them climbed the stone steps and breathed in the outside air. There was a sense of openness after leaving the closed underground atmosphere. Kuraf held the gem and let words slip out like a murmur. "[serious] We figured out the gem's mystery. But where to store it——we haven't solved everything yet." "[excited] But everyone's back to normal, so that's a total success, right?" Bronya laughed brightly. His golden eyes were narrowed as always. "[serious] Medically speaking, everyone's health is without issue." Natasha added seriously. Kuraf glanced down at the gem in her hand. In the daylight, the patterns were clear. Casually——truly casually——she turned it toward Dan Hen. The gem glowed faintly. "[surprised] Huh, why now——" All the blood rushed to her face. She hurriedly hid the gem behind her back. Dan Hen was looking at her. His reddish-purple eyes held her gaze quietly. "[serious] ……I know." Just two words. Two words that raced through her entire body. Her face burned. Her mind went white. "[excited] Ah———I knew it!!" Bronya threw both hands up and shouted. His voice echoed across the stone pavement. A researcher walking nearby turned around. Natasha——just barely——her expression stiffened. "[serious] I……see." Her gaze slipped away. "[angry] Don't laugh!! Bronya, don't laugh!!" "[laughing] Impossible!! I can't help it!! Because Dan Hen said he knows——!!" Bronya clutched his stomach. Natasha said "Calm down" while clearly not calm herself. Kuraf glared at Dan Hen with the gem still hidden behind her back. Dan Hen's gaze was averted. But——his ears were slightly red. --- When they returned to the Parnasse, the smell of the dining car greeted them. The auto-cooker was beginning dinner preparations. The wood-grain and brass interior gave the feeling of coming home. Natasha and Bronya went to return the gem to the cargo hold. They placed it in a shock-resistant case and locked it. Kuraf emphasized to Bronya: "[serious] Make sure it stays in the case this time. I don't want it rolling out again." "[serious] I got it! Leave it to me!" "[serious] I'll verify the lock as well." Natasha added seriously. Kuraf watched the two head toward the cargo hold, then made her way to the helm. The helm's star chart hologram activated the moment she entered, spreading out instantly. A three-dimensional map of the Yarulo sector floated before her. Small points of light marked planets. Blue lines stretched between stars——interstellar routes. The next destination. Kuraf settled into the pilot's seat and began inputting a route into the hologram. Orgein—a mining planet on the edge of the Yarulo sector, rich in metal resources——was their planned resupply stop. The Railkeeper Alliance had a branch there, so they could do maintenance. As she worked the controls, a presence appeared in the corridor. "[serious] Next destination decided?" Dan Hen appeared in the doorway, his arm resting against the frame. His silver hair caught the corridor's light. "[serious] Yeah. Stopping at Orgein for supplies. About five days on the interstellar route." "[serious] ……I see." Dan Hen leaned against the helm entrance. He didn't leave. Kuraf continued manipulating the hologram, still thinking about that "I know" from earlier. What did he mean? What did he know? Was he just observing that the gem had glowed? Or—— (Stop. Don't think about it.) She told herself, trying to finalize the route. At that moment. Pylon—an alert sounded. A notification appeared on the helm's alert panel. An alarm from the cargo hold. 'Case D lid opened. Object fall detected.' "[angry] We just locked it!!" She started to stand when Bronya's voice came from the corridor. "[surprised] Huh?! I'm sure I closed it properly?! Natasha, did you check the lock?!" "[scared] I did! But——it's glowing again!!" Faint light from the cargo hold spilled into the corridor. Dan Hen turned quietly back toward Kuraf. His purple eyes looked between the light and her, back and forth. Kuraf stood a