The needle went into Tom Webb's shoulder at an angle I had not intended. I watched the tiny bead of blood well up and knew, even before I counted, that I had missed the seventh point. One needle short. One error in a procedure that required seven perfect placements. The mistake was invisible to everyone but me, and that was the worst part.

"Seven needles, Doctor Kane," Tom said, looking at his arm with the simple curiosity of a man who trusted me completely. "You only did six."

The consulting room was small and poorly lit. The radiator clanked in the corner, making a sound like a dying animal. Outside, the wind blew dust across the parking lot.

"The seventh was not necessary," I said.

But it was. I knew it was. In the moment I should have been focusing on the needle, my mind had drifted to the letter that had arrived that morning from a colleague in the city. The letter spoke of a physician named Henry Blackwood, whose reputation had grown like ivy on a stone wall. I had been thinking of Blackwood when I should have been thinking about Tom Webb's shoulder.

I told him to leave.

Three days later, I encountered him at the grocery store, and he held up his arm as though it were a trophy. "Blackwood fixed me in two visits," he said, loud enough for the people in the produce aisle to hear. "Seven needles, seven points. Every time."

I told him to get out of my sight.

The lump appeared a week later.

It began as a small hardness beneath the skin, just below my right shoulder blade. I could feel it when I buttoned my shirt, when I reached for files on the high shelf, when I pressed my back against the chair in my office. I told myself it was nothing--a blocked pore, a minor irritation. I am a physician. I know the body.

But my wife, Martha, saw it when I undressed that evening. She gasped. The lump was the size of a pigeon's egg, purple at the center, surrounded by a halo of angry red.

"I will make an incision," I said, though my voice lacked the certainty I had worn like armor all my life.

Martha took the scalpel with trembling hands. She cut too shallow. The wound wept a little clear fluid and then closed again, leaving the lump trapped beneath the skin.

Five days later, the lump had grown to the size of an egg. It throbbed with a heat that kept me awake at night. I prescribed a poultice. I applied it twice daily. I told myself it was working.

But on the tenth day, when Martha undressed me to inspect the wound, the lump had swollen to the size of a grapefruit. It was soft at the center, fluctuant with pus, and the skin around it had turned a deep, bruised purple. Martha dropped the towel and covered her mouth with both hands.

"Larry," she whispered.

I examined it myself. The diagnosis was clear: a carbuncle, advanced, with the infection spreading into the subcutaneous tissue. If left untreated, it would enter the bloodstream. Fever. Delirium. Death.

I went to the neighboring clinics. Three physicians examined the boil and shook their heads. One suggested a poultice. Another suggested rest. The third, a young man with a smile that made my teeth ache, suggested I consult a surgeon.

I left without speaking to any of them.

The journey to Kansas City began at dawn. I wrapped myself in a woolen coat and got into my truck, telling myself that the stiffness in my back was merely from driving, not from the boil that pulsed with every heartbeat.

The rain began by midday.

It started as a drizzle and quickly became a deluge, the kind of Kansas rain that turns roads to mud and mud to a substance that pulls at your tires with each step. I was three miles from the town when I saw a barn ahead, its roof sagging under the weight of the water.

I pulled over and stumbled toward the door. My vision had gone gray at the edges. The boil on my back was a fire, a brand, a punishment. I reached for the doorframe and found nothing. My hand passed through empty air.

I fell.

Consciousness returned in fragments. Rain on my face. The smell of hay and diesel. A voice--male, unfamiliar, speaking with an urgency that cut through the fog in my head.

"Hello? Can you hear me?"

I opened my eyes. A man leaned over me, his face weathered by wind and sun, his eyes wide with something that might have been fear or might have been pity. Tom Webb.

He dragged me into the barn and pressed his fingers to my throat. I felt the pressure, distant and muffled, as though it were happening to someone else.

"The doctor," Webb said to someone--a woman, perhaps, or perhaps only the rain. "The doctor needs a doctor."

The night passed in a blur of movement and sound. Webb called an ambulance. The paramedics arrived in twenty minutes, their lights flashing through the rain. They loaded me onto a stretcher and drove me to the county hospital, where a man named Lynn examined me, frowned, and shook his head.

"I cannot treat this," Lynn said. "The infection has spread too far. We need a surgeon. Someone from the city."

Webb drove us back toward the town, then turned north. We arrived at a hospital on the edge of Kansas City, its windows bright, its doors automatic. Lynn called a man, and an hour later, a surgeon arrived.

"Let me see him," he said.

I tried to speak, but my tongue was thick and my mouth was dry. I could only watch as he knelt beside me, lifted my coat, and examined the boil.

He did not gasp. He did not recoil. He simply nodded, once, and opened his bag.

The incision was precise. He cut deep, deeper than Martha had ever dared, and the pus that followed was dark and thick and smelled of death itself. He scraped the wound with a tool I could not see in the bright light, removing the dead tissue layer by layer, until the wound was raw and red and bleeding freely.

Then he applied a paste that burned and cooled and burned again, wrapped the wound in gauze, and turned to Lynn.

"Get him to surgery. And bring broth. Strong broth."

Lynn nodded and disappeared down the hall.

Webb stood in the corner, his hands clenched, his face pale. He said nothing.

I do not know how long I was unconscious. When I woke, the room was quiet, the rain had stopped, and a woman--Martha, I realized--sat beside my bed, her eyes red from crying.

She told me everything. How Webb had found me in the mud. How he had called the ambulance. How he had searched the county hospital for a surgeon when he could have simply left me in the barn. How he had returned again and again, bringing water and bread and blankets, never asking for anything in return, never mentioning the words I had spoken on the street three weeks earlier.

"He did not have to do that," she said.

I closed my eyes. The boil was gone. The pain was gone. But something else remained--a weight in my chest that had nothing to do with infection.

The surgeon entered an hour later. He stood at the foot of the bed and looked at me with those same expressionless eyes.

"You will live," he said.

"Thank you," I whispered.

He nodded, once, and left the room. He did not say anything about cautionary tales or ledgers or pride. He simply nodded and left.

I lay in the silence that followed, staring at the ceiling, and felt the scar forming beneath my skin--not the one on my back, which would heal with time, but the one that would never heal at all. The scar of a man who was saved by the very person he had refused to acknowledge.

But the surgeon had not said anything. He had not spoken about pride or ego or wisdom. He had simply done his job. That was all.

I left the hospital two weeks later. I went back to my practice. I saw patients. I prescribed antibiotics. I told Tom Webb that his shoulder looked better. He nodded and said thanks and left.

The scar on my back ached every time it rained, and sometimes, in the fluorescent light of the office, when I undressed to change my shirt, I could see it--a twisted, purple line that ran across my shoulder blade like a brand.

I told myself it was just a scar. Nothing more. Nothing less.

Life went on. I saw patients. I prescribed antibiotics. I told Tom Webb that his shoulder looked better. He nodded and said thanks and left.

That was all.