3. Cao’s Algorithm

The paper crumpled in Leon's palm as the warning sank into his skin like the cold tip of an acupuncture needle. He scanned the crowd with peripheral vision, the champagne tray now a liability in his hands. The woman in the black suit had dissolved into the sea of investors and influencers, leaving behind only the two words that changed the geometry of the room. Every face now seemed turned slightly toward him. Every conversation seemed to pause when he moved.

He set the tray on a nearby standing table and walked, not toward the exit, but toward the restroom. Sudden flight would confirm guilt. A man who needed to urinate was invisible.

The restroom was marble and brass, the kind of luxury that converted factories acquired when they were reborn as cultural spaces. Leon locked himself in a stall, pressed his forehead against the cool metal door, and forced his breathing to slow. The folded paper was still in his hand. He smoothed it out and examined it under the dim recessed lighting.

The clerical script was precise, brush-like, but the ink was modern gel pen. The paper was ordinary stationery, the kind sold in any convenience store. No watermark, no microprinting. Whoever had written it had done so quickly, probably in the last hour, which meant the warning was reactive rather than premeditated. The woman knew something about the immediate threat, not the broader conspiracy.

Or she was part of the conspiracy, and the warning was a manipulation designed to make him trust her.

Leon flushed the toilet for authenticity, unlocked the stall, and washed his hands slowly. In the mirror, he watched the door. No one entered after him. The party continued its muted roar beyond the walls.

He needed to make a decision. The pendant was still around Cao Yichen's neck, still saturated with viable genetic material, still the most accessible path to the patient-zero data. The men who had framed him were inside the venue, which meant they knew he was here. Either they were waiting for him to incriminate himself, or they were waiting for him to succeed so they could take the sample from him.

Either way, the window was closing.

Leon returned to the main hall. The networking reception had shifted into its second phase—the serious investors had migrated to a roped-off VIP area near the stage, while the general attendees clustered around the open bar and the hors d'oeuvre stations. Cao Yichen stood at the center of the VIP area, flanked by two men who were too fit for business executives and too alert for event staff.

Private security. Leon recognized the bulge of concealed weapons beneath their jackets, the way their eyes swept the room in coordinated patterns. The warning had been accurate.

He grabbed a fresh tray of champagne and walked directly toward the VIP rope, his spine straight, his pace unhurried. The security guard on the left tracked his approach and held up a hand.

"Authorized personnel only."

"I have a message for Mr. Cao from the event coordinator." Leon's voice was calm, his Mandarin tinged with the faint accent of someone who had learned the language abroad. "There's a security issue with the livestream feed. She asked me to deliver it personally."

The guard's eyes flicked to his partner. In that moment of hesitation, Leon added, "It's about the Weibo posts. The threats. She thinks it's connected."

The words had the intended effect. Cao Yichen, who had been listening despite appearing not to, turned from his conversation and fixed Leon with the same heavy-browed gaze that had stared out from ancient portraits. His expression was unreadable, but his hand moved unconsciously to the jade pendant at his chest.

"Let him through."

The rope unclipped. Leon stepped into the VIP area, the champagne glasses trembling slightly on the tray. He was now three meters from the target, close enough to see the fine lines around Cao Yichen's eyes, the faint scar on his jaw that no amount of wealth had been able to erase.

"What security issue?" Cao Yichen's voice was low and controlled, the voice of a man accustomed to crisis management.

Leon lowered his own voice to match. "The posts threatening to complete Hua Tuo's surgery. The person who wrote them is claiming to have access to your neural interface data. The livestream team is worried about a hack during the final demo."

Cao Yichen's expression flickered—not fear, but something sharper. Recognition. "You work for the livestream team?"

"I'm with the venue's technical staff. I was asked to relay the message because they didn't want to cause a visible disruption." Leon gestured with the tray toward the stage. "They're running a diagnostic on the main feed now. They wanted to know if you'd prefer to delay the second demo or proceed with additional encryption."

The lie was complex enough to sound plausible. Every event had technical staff. Every technical staff member had access to the production team. And the threat of a hack was exactly the kind of problem that would be escalated quietly, without alarms, to avoid spooking the investors.

Cao Yichen glanced at his security team. "Get me the head of production. Now."

The guard on the left turned away, speaking into a wrist-mounted communicator. In that brief window, Leon executed the first part of his revised plan. He stumbled forward, just enough to lose balance, and the champagne tray tipped. Golden liquid arced through the air and splashed across Cao Yichen's white dress shirt.

The reaction was immediate. Cao Yichen stepped back, his hands rising reflexively. The security guards pivoted toward the threat. And Leon, in the chaos of apology and spilled alcohol, reached out as if to help and closed his fingers around the jade pendant.

The silk cord snapped with a soft whisper.

"I'm so sorry, Mr. Cao, I'm so sorry—" Leon was already backing away, the pendant clutched in his palm, his face a mask of mortified panic. "I'll get a towel, I'll get the cleaning staff—"

He didn't wait for a response. He turned and walked fast toward the restroom, not running but close to it, the pendant now slipped into his jacket pocket, its surface warm from Cao Yichen's skin.

Behind him, he heard Cao Yichen's voice, calm but edged with steel: "Find out who that man is. Now."

The restroom door swung shut behind Leon. He locked himself in the same stall, pulled out the jade pendant, and examined it under the light. The qilin carving was exquisite, centuries old, the jade smooth with handling. And at its mouth, the small dark cavity he had noticed earlier was indeed a compartment, sealed with a tiny gold cap.

He unscrewed the cap with careful fingers. Inside, nestled in a bed of silk thread, was a single capsule. Not an ancient herbal pill, but a modern pharmaceutical capsule, transparent, filled with a fine crystalline powder that glittered faintly in the light.

Leon didn't have time to analyze it. He swabbed the pendant's surface with a sterile cotton swab from the emergency kit he had assembled—cotton, alcohol wipes, ziplock bags—and sealed the sample carefully. The pendant itself he rewrapped in a clean handkerchief and returned to his pocket. He couldn't leave it behind; its absence would confirm theft. He would have to return it somehow, or dispose of it, but that was a problem for later.

The countdown timer on his burner phone showed 58:22:14.

He needed to get to the Shenjing Neural Systems research facility in Pudong before the sample degraded. That gave him until approximately four in the morning, accounting for the six-hour window. The facility was a thirty-minute drive from the Long Museum. He could make it.

But when he emerged from the restroom, the event had changed. The security guards were now moving through the crowd with photographs—screenshots from the venue's security cameras, probably, showing Leon's face. The coat check area was cordoned off. And near the main entrance, two uniformed police officers were talking to the event coordinator.

Leon reversed direction and walked toward the kitchen. Every catering venue had a back exit, usually propped open for deliveries and smoke breaks. He pushed through swinging doors, past a startled line cook, and emerged into a narrow alley lined with empty crates and industrial waste bins.

The alley was empty. The night air was cool and damp. Leon allowed himself one deep breath, then started walking toward the nearest metro station, his hand pressed against his jacket pocket where the pendant rested beside the needles.

He was three blocks from the venue when the woman in the black suit appeared again, stepping out of a doorway like a ghost materializing from stone.

"You got the sample." It wasn't a question.

Leon stopped walking. "Who are you?"

"My name is Shen Li. I worked with your father before he died." She was older than he had initially thought, mid-forties perhaps, with the kind of weathered elegance that came from a life spent outdoors rather than behind a desk. "The men inside the venue work for an organization that calls itself the Divine Surgeon. They've been tracking you since your grandfather's video was triggered."

"The Divine Surgeon," Leon repeated. "That's what the video called itself. The AI that controls the inheritance."

"It's not just an AI. It's a network. People who believe that Hua Tuo's medical knowledge should be used without ethical constraints—that the Qing Nang Code contains techniques the world has suppressed for two thousand years. They want you to complete the list, but not for the inheritance. They want you to unlock the full Code so they can take it from you."

Leon's hand closed around the acupuncture needles. "Why should I believe you?"

Shen Li reached into her jacket and pulled out a photograph. It was old, creased, the colors faded: a group of people standing in front of a traditional Chinese medical clinic, smiling at the camera. Leon recognized his father immediately—younger, thinner, his arm around a woman who looked like a younger version of Shen Li.

"Your father was murdered," Shen Li said. "Not in an accident, like you were told. He was killed because he refused to complete the third task on the list. The Divine Surgeon executed him, and they made it look like a car crash."

The photograph trembled slightly in her hand. "They need a Hua to complete the protocol. You're the last one. If you fail, they'll kill you too. If you succeed, they'll extract the Code from you using the neural interface technology that Cao Yichen built."

Leon stared at the photograph. His father's face smiled back at him, frozen in a moment of happiness that had occurred years before the accident that had supposedly taken his life. He remembered the funeral, the closed casket, his mother's silence whenever he asked about the details.

"Why are you helping me?"

"Because I loved your father," Shen Li said. "And because the Divine Surgeon is using you as a weapon to destroy the Cao family. Once that's done, they'll destroy you too. I want to help you survive long enough to make a different choice."

She handed him a keycard. "Service entrance to Shenjing Neural Systems. The guards change shift at two in the morning. There will be a seventeen-minute window. Use it to get the patient-zero data, then get out. I'll contact you again after you're clear."

Leon took the keycard. "If this is a trap—"

"If this were a trap, I would have let the security guards catch you ten minutes ago." She stepped back into the doorway. "Your father's last words to me were that you were the only one who could finish what Hua Tuo started without becoming a monster. Don't prove him wrong."

She was gone before Leon could ask what that meant. The alley was empty again, the distant sounds of the party fading into the ambient hum of the city.

Leon looked at the keycard in his hand, then at the countdown timer on his phone. 57:48:31.

He had seventeen minutes to infiltrate one of the most secure research facilities in Shanghai, using a keycard from a woman he had just met, to steal data that could either save his life or end it. And somewhere in the digital architecture of the Divine Surgeon, the ghost of his grandfather was waiting to see whether the last heir of Hua Tuo would become a surgeon or a corpse.

He started walking toward the metro station. Behind him, the Long Museum's converted warehouse glowed against the night sky, its windows full of light and laughter and people who had no idea that a two-thousand-year-old medical feud was about to claim its next casualty.

The metro at midnight was half-empty, the fluorescent lights casting everyone in a sickly pallor. Leon sat in a corner seat, the pendant and the keycard both heavy in his pockets, and thought about his father's last words to him, spoken three days before the accident: "There are things in our family history I never told you. Things I tried to protect you from. If anything ever happens to me, find the needles. They'll tell you what to do."

At the time, Leon had assumed his father was being melodramatic, the kind of cryptic pronouncement that aging parents made when they started contemplating their mortality. Now he understood. His father had known he was being hunted. He had left clues, breadcrumbs, and a son who could read ancient medical texts but had no idea how to defend himself against a digital assassination.

The metro announcement chimed for the next station. Leon looked up and saw, reflected in the dark window, the face of one of the security guards from the venue. The man was three seats away, his eyes fixed on his phone, his posture deliberately casual.

They had followed him.

Leon stood before the doors opened, positioning himself near the exit. The guard stood too, his phone still in his hand, his other hand moving toward his jacket.

The doors opened.

Leon stepped onto the platform and immediately broke into a run, weaving through the sparse late-night crowd toward the exit stairs. Behind him, he heard the guard's footsteps accelerate, the rhythmic pound of pursuit echoing off the tiled walls.

He took the stairs three at a time, burst through the turnstile, and emerged onto the Pudong street. The research facility was six blocks away, its glass tower visible against the light-polluted sky. Leon ran toward it, his lungs burning, the acupuncture needles clicking softly against each other with every stride.

He didn't look back. He didn't need to. The sound of the guard's footsteps was still there, closer now, and somewhere in the digital infrastructure of the Divine Surgeon, algorithms were adjusting their predictions, updating his threat level, and preparing the next phase of the trap that had begun with a stolen social media account and would end, if Leon failed, with the completion of a murder that had been two thousand years in the making.

The tower loomed ahead, its lobby dark except for security lighting. Leon had sixteen minutes before the guard shift change. He had a keycard that might or might not work. And he had a pendant that contained a capsule of crystalline powder that, he now suspected, was not medicine at all.

He slipped into the shadows beside the service entrance and waited, counting the seconds, watching the street for the guard who was surely still following him. The countdown timer on his phone pulsed once.

57:02:44.

The first incision was about to begin.