That evening, Shi Bei returned to her apartment carrying armfuls of everyday clutter and closed the door behind her.
Coming out after a shower, even the extraordinarily cramped room felt slightly more settled and comfortable.
Shi Bei sat down at her desk.
After a long pause, she pulled out a sticky note from her coat pocket.
Staring at those two lines of Traditional Chinese characters—scribbled carelessly yet retaining a clear, refined elegance—the spot on her head where the glass had struck began to ache faintly again under the force of psychological suggestion.
She quickly comforted herself, realizing that today had yielded a huge harvest.
She had originally intended to find a way to get Kong Lingrou’s address; she hadn’t expected Kong Lingrou to come straight to her door instead.
It could be considered a huge success.
Shi Bei opened her drawer and tossed the sticky note inside.
She dazed out for a moment, attempting to erase the related memories from her mind.
After a while, it proved a bit of a failure.
“…”
After sitting there for half a day, she pulled open the drawer again and retrieved the sticky note.
Tonight’s moon was extraordinarily bright; even without turning on the lights, the moonlight pouring into the room was enough to clearly read the handwriting on the paper.
Compared to many years ago, there was no noticeable change in the handwriting.
Her long eyelashes drooped as she stared at it quietly and peacefully.
After a moment, her fingertip unconsciously brushed against the edge of the characters, ever so gently.
During these days, Shi Bei didn’t go out at all except to complete administrative procedures and attend mandatory orientation sessions.
Her lab mentor was currently abroad for a conference. After a brief exchange via email, her mentor gave her the contact information for a senior Chinese student in the lab.
The senior student explained various matters to her—ranging from academics to daily life—sending messages at lightning speed. Complete with text and photos, she was so warm and enthusiastic that Shi Bei didn’t even know how to respond.
Senior Student: [If you run into any problems, feel free to come talk to me anytime! Things about daily life, or anything at all.]
Senior Student: [By the way, I saw that your resume is extremely impressive. Are you interested in taking on a side gig?]
Senior Student: [Of course, it definitely pays~]
Shi Bei: …
She quickly typed “I don’t have time,” but after hesitating for a long while, she deleted it. Considering that she would have a lot of contact with this senior student in the future, it would be best to lend a hand, even if the task didn’t offer high compensation.
null: [If it’s a project I’m good at, I can take it.]
The April weather was neither cold nor hot. Aside from occasionally going down to throw out the garbage, Shi Bei never stepped downstairs again. Food deliveries were left at her door, and when the occasional courier knocked, she pretended not to hear.
Just after a heavy rainstorm stopped one day, the clear voices of children came from downstairs.
Shi Bei, who was typing on her keyboard, paused her movements. She was somewhat surprised in her heart—why would children be speaking Japanese downstairs at her building?
Only after a moment did she realize, as if waking from a dream: she was currently in Tokyo.
She hurriedly picked up her phone, cleared a mountain of app notifications, and tapped through them one by one to check if she had forgotten anything.
She saw a reminder pop up on her calendar: Classes start tomorrow.
Shi Bei threaded her way through the congested crowd streaming off the morning rush-hour train, checking the station name and direction against her navigation map once more.
The trip went smoothly. By the time she arrived, there were only a scattered few people in the classroom.
Dressed in an unremarkable hoodie, she sat in the very back row of the classroom, occasionally looking up at the people walking in. While observing, she was unexpectedly approached.
“You’re taking this class too?”
Shi Bei: “…”
“Do you still remember me?” Kong Lingyu sat down beside her, speaking in a very friendly manner: “I’m Kong Lingrou’s younger sister. My name is Kong Lingyu.”
“Isn’t this Kong Lingrou’s class?”
“I’ve been subbing for Period 1 classes all along.” Kong Lingyu’s casual sentence completely shattered all of Shi Bei’s plans. “Are you here looking for her?”
“No… I’m not looking for her.”
“That’s good. Right now she seems to be in some other city or place.”
“Traveling?”
“Uh, you’d have to ask her about that. Didn’t she tell you?”
Shi Bei didn’t continue the topic. She took her laptop out of her backpack, switched the subject, and said, “I just happened to be a bit interested in this class.”
“Oh, I see.”
This period was supposed to be taught in English, but perhaps due to interdisciplinary reasons, Shi Bei could barely understand a word, whether the professor spoke in English or Japanese.
At times, she couldn’t even tell whether the professor was currently speaking English or Japanese.
Seeing the bewildered expression floating on Shi Bei’s face, Kong Lingyu showed a amused, spectating smile, then immediately offered comfort: “It’s fine, everyone struggles to understand when they first arrive. Give me your email, and I’ll send you the lecture notes from the earlier classes. Once you look over the notes, you’ll get used to it quickly.”
“Thank you…”
“You’re welcome. Though getting too used to it isn’t necessarily a good thing either—before you know it, your own English accent turns into this too.” Kong Lingyu smiled, then added, “Let me add your contact info. If you have any questions in the future, you can always ask me.”
Shi Bei turned her head to look at her earnestly, then smiled genuinely: “Thank you so much.”
Kong Lingyu was an innocent, enthusiastic girl who loved making friends.
Shi Bei had tracked and recorded her social media updates for two or three years, mastering a vast knowledge of her preferences. Under Shi Bei’s deliberate attentiveness, the two of them quickly became close.
During class, Shi Bei glanced at Kong Lingyu, who was playing on her phone.
“A new escape room shop just opened near the school. It’s only a ten-minute walk away. Want to go play after class?”
“Really? That’s awesome! How did you know I was just thinking about playing there?”
The old professor on the podium basically didn’t take attendance.
After sitting for a while longer, Shi Bei suddenly began packing up her things.
When the professor turned around to fiddle with the projection screen, the two girls exchanged a glance. With perfect tacit understanding, they stood up and tiptoed out the back door on quiet footsteps.
It was merely cutting class a bit early, yet the path out of the school gates felt as if the scenery had transformed entirely.
The sky was so blue it had a transparent quality, with faint clouds resembling chalk marks casually scribbled on a blackboard.
Kong Lingyu gigglingly linked her arm with Shi Bei’s. Following the navigation, they zig-zagged through twists and turns for over ten minutes before arriving at the escape room shop. All interactions with the staff were handled by Kong Lingyu, while Shi Bei could only catch a few broken words flying past her ears.
After storing their personal belongings, they entered the secret room.
The interior was decorated like a medieval alchemist’s basement. Crimson wallpaper was covered with sheets of parchment paper, all inscribed with obscure formulas and symbols.
“Woah—” Kong Lingyu’s eyes sparkled brightly. She instinctively tried to grab Shi Bei next to her, only to catch empty air.
Shi Bei had already walked ahead.
Among the clutter of decorative parchment papers on the wall, there was a poem written in English if one looked closely. Framed in walnut wood right in the center of the wall, the poem bore a unique title:
The Right of Way.
The right of way is theirs who have the soul;
The sacred strength to carry out a goal.
This is the law of Nature, that the deed
Should be in him who has the power to lead.
And Euclid’s elements are graven in stone.
“Doesn’t this poem feel like it wasn’t finished? The ending cuts off a bit unnaturally.” Kong Lingyu followed her gaze to look at the framed poem together, pointing at the last line as she remarked offhandedly: “Could the closing line be some kind of clue?”
Shi Bei pondered for a moment, finding it quite interesting.
She couldn’t help softly reading the final line aloud:
“And Euclid’s elements are graven in stone.”
The literal translation was very simple: Euclid’s principles are carved into stone.
Kong Lingyu turned her head sharply and stared at Shi Bei.
Having spent these years getting thoroughly accustomed to Japanese-style English, suddenly hearing a standard, aristocratically polished English accent identical to her older sister’s inevitably gave her a startle.
Shi Bei: “Let’s go look around and see if there are any stones or things like that.”
Kong Lingyu gave an affirming nod and began searching high and low.
She thoroughly enjoyed the process of digging through strange boxes like a treasure hunt. Touching here and feeling there, in less than two minutes she actually found a terribly heavy briefcase.
“Come quick! There are lots of stones inside this box, and there are lots of numbers on the stones too.”
Engraved on the yellow-sand-covered stone blocks were rounded Arabic numerals, with tiny stylized English markings in the bottom left corners.
As Kong Lingyu wiped the dust off the stones, she laid them out one by one.
Her eyes were shining bright. Playing such an immersive game for the first time, her face flushed slightly with excitement inside this scene crafted with fine props and detail.
“I found the numerical ordering,” Shi Bei said, holding a piece of paper she had grabbed from somewhere. “If we solve it using the Euclidean algorithm, that should do it.”
Kong Lingyu immediately laughed: “No way. There are still so many things we haven’t even looked at! If you can just calculate your way out, wouldn’t the escape room designers have created all this stuff for nothing?”
Shi Bei casually picked up a quill prop and said in an utterly flat tone:
“The other clues are probably meant for people who don’t know how to do the math.”
Kong Lingyu: “…”
She decided not to argue with Shi Bei; as long as Shi Bei could enjoy doing her math, even if the answer turned out wrong in the end, it was fine.
So she pointed off to the side and said, “Then I’ll go look for other things first.”
Shi Bei lowered her head and began writing out the calculation process.
Kong Lingyu walked and inspected along the way, tapping her hand against the wall to try and find anything unusual, finally stopping in front of a tightly shut and locked door.
“It’s open,” came Shi Bei’s voice from not far away.
“What?” Kong Lingyu, hearing the words clearly, doubted her own ears.
She turned around and saw Shi Bei walking out from the darkness, holding her hand out toward her.
In her palm lay an antique, amber-yellow key.
“What is this?! Where did you find it?”
“The calculated digits unlocked the box at the entrance. The key was inside the box.”
“…We’ve only been in here for fifteen minutes!”
“I suppose so.”
Kong Lingyu stared at her in disbelief for a moment, then lowered her head to check her wristwatch.
The brief passage of time was no illusion.
The staff had mentioned that it usually takes a team of six people about an hour and a half to solve everything. There were still tons of unexamined items left in the room.
“How did you calculate that? Is a password something that can just be calculated?!”
“The Euclidean algorithm is also known as the division algorithm. The index on the sheet corresponds to the two numbers obtained from the stones found. Taking those two numbers, you calculate their greatest common divisor. The resulting four digits form the combination to open the codebox.”
After explaining, Shi Bei added: “You can keep playing if you want.”
Kong Lingyu spent half a day trying hard to load those words into her brain before finally grasping it.
The poem on the wall read: Euclid’s elements are graven in stone.
So Shi Bei copied down the numbers from the numbered stones against the chart and plugged them into the formula hinted at in the poem to calculate the passcode.
Logically she understood it, but emotionally she absolutely refused to accept a fun escape room turning into an immersive math test.
“I bet this counts as an easter egg in the escape room design at most,” Kong Lingyu said with a look of despair. “That’s definitely not how normal people play it!”
Suddenly, she remembered something else.
She led Shi Bei over to the door with the padlock from earlier and said, “Since you’re so smart, do you have a way to open this door?”
Shi Bei felt her pocket; she happened to have a hairpin on her.
She picked up the lock to adjust the angle, pinched the hairpin tightly with her other hand, poked it inside, and twisted hard, producing a faint click.
Holding the easily opened lock, she then reminded her: “This looks like an unfinished area of the shop.”
“…”
Kong Lingyu stared dumbfounded at the harmless-looking girl in front of her.
What just happened?
She picked the lock?!
Well, she was the one who asked her to figure out a way to open it… but was it really reasonable for her to do it so naturally and smoothly??!
This gentle and honest classmate actually possessed such sharp, rogue skills?
Behind the door was absolutely nothing.
To be precise, in the excessively pitch-black environment, nothing could be seen at all.
Kong Lingyu tried hard to compose her shocked state of mind, stepping onto the ledge in front of the door and peering inside a few times.
Behind her, Shi Bei, who possessed superior eyesight, said softly: “Be careful, there’s a somewhat deep pit ahead.”
“Huh?” Borrowing the faint light behind them, Kong Lingyu could barely feel that there was indeed a pit. She sat down facing the darkness, dangling her legs over the edge to gauge how deep it was underneath.
“It shouldn’t be too deep, a bit over one meter.”
Shi Bei was curious: “Can you judge the height even without touching the bottom? Plus, your legs aren’t a meter long.”
Kong Lingyu: “?”
Shi Bei walked up beside her to observe.
Just as she was intently staring into that patch of darkness to calculate the depth, she heard Kong Lingyu say in a teasing tone:
“How about you jump down and try?”