“The patient’s name?”
“Oh Gak.”
“Age?”
“Thirty-one.”
“When and how was he exposed?”
Ryu Dan carefully separated what he knew from what he inferred. Oh Gak claimed he had been stabbed beneath the arm with a needle at the eastern warehouse two mornings ago. Ryu gave the time it had taken him to walk back to the inn, his temperature and pulse when he first collapsed, the blue-black blood edged in pale green, how much water they had used to cool him, and how many times he had vomited.
The younger Tang Soryeong did not interrupt him once. Only after she finished recording the details did she look at his hand.
“Why is your right hand trembling?”
“That has nothing to do with the patient.”
“The condition of someone who handled the patient has everything to do with him. Do you have any cuts on that hand?”
“No.”
“Show me.”
Ryu opened his palm. She checked even the spaces between his fingers. Inside him, future Tang said, *Good. At least I understood the basics back then.*
Baek Mugyeol replied, *By your standards, did testing poison on yourself also qualify as basic practice?*
Tang’s echo went cold.
*Do not mention that.*
The younger Tang could not hear either of them. She verified Ma Yeongsun’s signature on the seal, then chose Nam Sogun as Azure Peak’s witness.
The younger Baek asked, “Why not me?”
“You looked at the token before you looked at the patient. Hero Nam has not stepped on the contaminated floor since he entered.”
Nam looked uncomfortable. Baek fell silent for a moment, then stepped back three paces.
Future Baek muttered, *Her standard is rational.*
Tang laughed.
*You never did learn to say the compliment aloud.*
Ryu ignored them both. The younger Tang broke the seal. With a thin silver needle, she took a trace of poisoned blood from the dish and dissolved it in three medicinal solutions. The first turned black, the second a murky white, and the third a vivid yellow.
“It is Green Vein Poison. But there is something wrong with the binding agent.”
Ryu did not repeat what future Tang had told him. He waited to see what the physician of the present would find.
The younger Tang raised the yellow solution toward her nose, then put it down at once.
“It isn’t only lime oil. There is an adhesive refined from pine resin. I think it is meant to keep the mixture from settling when dissolved in oil.”
“Oil?” Nam asked.
“I said it was a possibility. Do not treat it as a conclusion yet.”
She went to the shed where Oh Gak lay. After examining his eyelids, tongue, and fingernails, she pressed his abdomen. Oh Gak screamed.
“If you press something that hurts, it hurts!”
“I was checking whether you were alive.”
“You can check my pulse!”
“It was faster to check whether your mouth was alive.”
Future Tang sounded impressed.
*That truly is me.*
The younger Tang’s expression darkened when the examination was done.
“The poison is not leaving his body. It is changing where it sits.”
“What does that mean?”
“The emergency treatment protected his heart and brain, but the binding agent has adhered to his organs. His fever will fall, then rise again this evening. If we use the standard Green Vein antidote, the binding agent may dissolve first and release the poison all at once.”
Future Tang immediately recited a prescription.
*Three mace of Clear Spirit Herb, one mace of White Blossom Root, half a candareen of borneol. Cool the organs first, then administer the antidote powder.*
Ryu asked, “Will that work on this binding agent?”
*I practically created the field of Green Vein Poison treatment.*
“You said you had never seen this binder at this time.”
*The principles are the same.*
The younger Tang stopped with one hand inside her medicine case.
“I don’t have enough Clear Spirit Herb.”
Her future self responded at once.
*There is a completed prescription in the eastern clinic’s underground medicine vault, behind the third cabinet. Go in tonight and steal it. Turn the poison snake beneath the door handle twice to the right and it will stop.*
Ryu stared in disbelief.
“You want me to rob your own house?”
The younger Tang turned around.
“Who said that?”
“No one. The guest inside my head is rather extreme.”
“Has the poison reached your brain?”
“We are considering that possibility.”
Future Tang snapped, *The family will choose the secret formula over the patient. I lived through it.*
Her memory touched Ryu. Tang Soryeong at twenty-one, cutting small wounds into her own arm night after night and dripping poison into them. Her father’s pharmacy filled with unfinished prescriptions. Her elder brother Tang Jun warning that if the formula leaked to Azure Peak, the entire family would be ruined. She had tried to prove everything alone. She survived, but lost sensation in her fingertips, and the secret became leverage for others to use against her.
But that memory was not the young woman standing before him now.
“Physician Tang,” Ryu said. “Can you release the completed prescription?”
Her face closed.
“It is a secret formula of the Tang Family.”
“Even if people die?” the younger Baek demanded.
“Does Azure Peak paste its sword manuals on market walls? The method for curing poison touches the method for making it. If the completed formula spreads, someone may create something worse than Green Vein Poison.”
Baek opened his mouth. Ryu spoke first.
“We are not asking for everything.”
Both of them looked at him.
“What we need is an emergency procedure anyone can follow if the same symptoms appear in the market. The Tang Family can retain the formula and the poison ratios. Release only the steps that will keep people alive until nightfall.”
The younger Tang did not answer.
Ma entered the shed carrying a bowl of porridge.
“If you’re finished arguing, feed the patient.”
“His organs are sensitive right now—”
“Which is why I made plain porridge. If he can’t eat it, you can.”
The younger Tang inspected its thickness and smelled a spoonful.
“Add only a little more salt. Feed him two spoonfuls at a time. More than that and he may vomit.”
Ma handed the bowl to Ryu.
“You heard her.”
She did not demand the secret formula or argue the Tang Family’s rights. She decided how much to feed the man now.
The younger Tang watched her for a long time. Then she took a small knife from her medicine case.
Future Tang spoke urgently.
*Stop her. That is for self-testing. If she takes the poison first, she can observe the change and alter the prescription.*
The younger Tang was already rolling up her sleeve.
Ryu caught her wrist.
“No.”
“Let go. If I apply a minute amount to the skin and observe the response, I can determine the binder’s properties—”
“We already have one patient. Why make it two?”
“I can learn the answer fastest.”
“And if you collapse, who writes the prescription?”
“There is no other way.”
He heard the desperation beneath her words: the burden of protecting her family’s secret and saving a life at the same time. The habit of placing her own body between two responsibilities because neither could safely be entrusted to anyone else. The future Poison Sovereign remembered it as cold resolve. To Ryu, it looked like the frantic responsibility of a young physician.
He did not release her wrist.
“Observe the changes already occurring inside Oh Gak. Do not create a new case. Ask the living patient.”
“You want to inflict more pain on him?”
“No. We record his urine, sweat, and temperature by the hour. We test the current sample separately with oil and heat. Azure Peak can send people to find whether the same oil has entered the market.”
Nam nodded.
“I will investigate the registry of market oil sellers.”
The younger Baek said, “I’ll search the warehouse—”
“Junior Brother Baek,” Nam said quietly.
The delegation from the previous day still stood. The younger Baek went rigid, then yielded.
“Senior Brother Nam will determine the routes. I will serve as escort.”
Future Baek closed his eyes as though listening to the sentence a second time.
The testing continued for two hours. The younger Tang collected Oh Gak’s sweat on paper and compared the changes in color. Ryu kept the brazier at a constant temperature. Ma numbered every cup they used. Following Nam’s directions, Baek escorted samples of oil back from the market.
In the third oil, the Green Vein residue left on the dish dissolved. When they heated it, pale green smoke rose.
The younger Tang went white.
“They are not using oil merely to transport the poison. They mean to release it when the oil is heated.”
“Then it may already have reached the market,” Baek said.
“The evening market has not opened yet,” Ryu replied. “Write the emergency procedure first.”
The younger Tang spread out a sheet of paper. For a long time, her brush did not move.
A rider arrived outside bearing the Tang Family crest. He presented her with a sealed letter. The moment she read it, her expression hardened.
“My elder brother orders me to transfer the sample and patient to our clinic immediately, and to release no prescription to Azure Peak.”
Future Tang sounded bitter.
*See? Nothing changes.*
Ryu returned the letter to her.
“What will you do?”
He could have frightened her with the future. He could have told her that if she proceeded alone, she would ruin her hands; that her family’s attempt to protect a cure would help create the Poison Sovereign they feared. But those were conclusions from another life. This young woman needed a choice, not an order.
She looked at Oh Gak. He was spending every scrap of strength he possessed on eating the porridge.
“I will not release the completed antidote formula.”
The younger Baek frowned.
“But I will publish cooling and isolation procedures for the moment of exposure, how to maintain respiration, which medicinal ingredients must not be used, and how to regulate the pulse until the patient reaches a physician. I will omit the proportions of Green Vein Poison and any medicinal quantities from which they could be derived. The formula remains Tang Family property, and revisions to the emergency procedure must be approved by a Tang physician.”
Ryu asked, “Who will keep it?”
“One copy with the Tang Family. One with Azure Peak.”
Ma flicked a bead across her abacus.
“Then no one will be able to use it when the two of you are fighting.”
The younger Tang looked at her.
“We will keep a third copy at Return Inn. Both families will seal it, and Innkeeper Ma may open it in an emergency.”
“Why me?”
“Because you saved the patient here.”
“Will you pay a storage fee?”
The younger Baek sighed.
“Azure Peak will pay half.”
“Why half?” the younger Tang demanded. “We treated the patient—”
“I meant your family would pay the other half.”
“I need to ask our family head.”
Ma collected the paper from between them.
“I’ll discuss the money. You two write down how to keep people alive.”
At last, the younger Tang raised her brush.
As she wrote the first line, the second core inside Ryu gave a clear, complete pulse. Cold, delicate energy settled into his dantian. It did not belong to him yet. He could only borrow its path for seven heartbeats. But it was far more distinct than it had been when the door opened.
Future Tang silently watched her younger self write.
*I wasn’t hiding it because I was weak.*
Ryu said nothing.
*I was trying to protect too many things, so I carried them alone.*
“Is understanding that part of medicine?”
*At least it isn’t poison.*
Near evening, Oh Gak stood without assistance. His legs shook, but he crossed the shed’s threshold on both feet.
“Can you walk?” Ryu asked.
“I’ll have to if I mean to repay ten taels.”
Behind him, Ma said, “Medicine brings it to twelve.”
Oh Gak nearly collapsed again. The younger Tang caught his arm.
“You cannot travel far yet. Instead, tell us exactly where the warehouse entrances are and what the bell signals mean.”
Oh Gak described the west door, the ledger hidden in the roof beam, and the ramp descending underground. At the end, however, he shook his head.
“If they know I survived, they’ve already moved everything. Deputy Leader Jang never uses the same route twice.”
The warehouse layout from the failed future was no longer reliable.
A scouting disciple ran in from outside.
“Carts have begun leaving the eastern warehouse! Deputy Leader Jang has gathered the laborers inside, and they are moving the blue-banded barrels west first.”
The younger Baek seized his sword.
“We strike now.”
The younger Tang blocked his path.
“If you shatter a poison barrel with your sword, the entire market is in danger. We establish an isolation perimeter first.”
“If we delay, the carts escape.”
“If we rush, the workers die.”
Behind them, their two future echoes spoke at the same time.
*Command must be unified.*
*Medical judgment comes first.*
Between four competing voices, Ryu opened the warehouse map. An uncertain future, present symptoms, intelligence from the surviving Oh Gak, and the roads Nam had investigated now shared one sheet of paper.
“You are both right. Which is why one person cannot control all of it.”
He pointed out the western exit to Nam, the poison barrels and laborers to the younger Tang, and the interior trap line to the younger Baek.
“Who carries the map?” Nam asked.
“I do.”
Ma looked at Ryu’s right hand.
“You’re planning to use that strange power again.”
“I’ll avoid it if I can.”
“And if you can’t?”
Ryu did not lie.
“For no more than three heartbeats.”
Ma tugged his belt tight and retied the knot, as firmly as if she were checking her ring of keys.
“Come back alive. And take my tray.”
“As a weapon?”
“As a loan. Dent it and you pay.”
Ryu accepted the tray.
One bell rang from the direction of the warehouse.
The man who should have died recognized it.
“That’s the departure signal,” Oh Gak said.
This time, sword, medicine, and roads moved separately. Ryu carried the weight between them.