It was ten days short of Candlemas, 1814, and an Atlantic wind carried shivers of cold rain that slapped on narrow cobbled alleys, spilt from the broken gutters of tangled roofs, and pitted the water of St Jean de Luz’s inner harbour. It was a winter wind, cruel as a bared sabre, that whirled chimney smoke into the low January clouds shrouding the corner of south-western France where the British Army had its small lodgement.

A British soldier, his horse tired and mud-stained, rode down a cobbled street in St Jean de Luz. He ducked his head beneath a baker’s wooden sign, edged his mare past a fish-cart, and dismounted at a corner where an iron bollard provided a tethering post for the horse. He patted the horse, then slung its saddle-bags over his shoulder. It was evident he had ridden a long way.

He walked into a narrow alley, searching for a house that he only knew by description; a house with a blue door and a line of cracked green tiles above the lintel. He shivered. At his left hip there hung a long, metal-scabbarded sword, and on his right shoulder was a rifle. He stepped aside for a woman, black-dressed and squat, who carried a basket of lobsters. She, grateful that this enemy soldier had shown her a small courtesy, smiled her thanks, but afterwards, when she was safely past him, she crossed herself. The soldier’s face had been bleak and scarred; darkly handsome, but still a killer’s face. She blessed her patron saint that her own son would not have to face such a man in battle, but had a secure, safe job in the French Customs service instead.

The soldier, oblivious of the effect his face had, found the blue door beneath the green tiles. The door, even though it was a cold day, stood ajar and, without knocking, he pushed his way into the front room. There he dropped his pack, rifle, and saddle-bags on to a threadbare carpet and found himself staring into the testy face of a British Army surgeon. “I know you,” the Army surgeon, his shirt-cuffs thick with dried blood, said.

“Sharpe, sir, Prince of Wales’s Own…“

“I said I knew you,” the surgeon interrupted. “I took a musket-ball out of you after Fuentes d’Onoro. Had to truffle around for it, I remember.”

“Indeed, sir.” Sharpe could hardly forget. The surgeon had been half drunk, cursing, and digging into Sharpe’s flesh by the light of a guttering candle. Now the two men had met in the outer room of Lieutenant Colonel Michael Hogan’s lodgings.

“You can’t go in there.” The surgeon’s clothes were drenched in prophylactic vinegar, filling the small room with its acrid scent. “Unless you want to die.”

“But…“

“Not that I care.” The surgeon wiped his bleeding-cup on the tail of his shirt then tossed it into his bag. “If you want the fever, Major, go inside.” He spat on his wide-bladed scarifying gouge, smeared the blood from it, and shrugged as Sharpe opened the inner door.

Hogan’s room was heated by a huge fire that hissed where its flames met the rain coming down the chimney. Hogan himself was in a bed heaped with blankets. He shivered and sweated at the same time. His face was greyish, his skin slick with sweat, his eyes red-rimmed, and he was muttering about being purged with hyssop.

“His topsails are gone to the wind,” the surgeon spoke from behind Sharpe. “Feverish, you see. Did you have business with him?”

Sharpe stared at the sick man. “He’s my particular friend.” He turned to look at the surgeon. “I’ve been on the Nive for the last month, I knew he was ill, but…” He ran out of words.

“Ah,” the surgeon seemed to soften somewhat. “I wish I could offer some hope, Major.”

“You can’t?”

“He might last two days. He might last a week.” The surgeon pulled on his jacket that he had shed before opening one of Hogan’s veins. “He’s wrapped in red flannel, bled regular, and we’re feeding him gunpowder and brandy. Can’t do more, Major, except pray for the Lord’s tender mercies.”

The sickroom stank of vomit. The heat of the huge fire pricked sweat on Sharpe’s face and steamed rain-water from his soaking uniform as he stepped closer to the bed, but it was obvious Hogan could not recognize him. The middle-aged Irishman, who was Wellington’s Chief of Intelligence, shivered and sweated and shook and muttered nonsenses in a voice that had so often amused Sharpe with its dry wit.

“It’s possible,” the surgeon spoke grudgingly from the outer room, “that the next convoy might bring some Jesuit’s bark.”

“Jesuit’s bark?” Sharpe turned towards the doorway.

“A South American tree-bark, Major, sometimes called quinine. Infuse it well and it can perform miracles. But it’s a rare substance, Major, and cruelly expensive!”

Sharpe went closer to the bed. “Michael? Michael?”

Hogan said something in Gaelic. His eyes flickered past Sharpe, closed, then opened again.

“Michael?”

“Ducos,” the sick man said distinctly, “Ducos.”

“He’ll not make sense,” the surgeon said.

“He just did.” Sharpe had heard a name, a French name, the name of an enemy, but in what feverish context and from what secret compartment of Hogan’s clever mind the name had come, Sharpe could not tell.

“The Field Marshal sent me,” the surgeon seemed eager to explain himself, “but I can’t work miracles, Major. Only the Almighty’s providence can do that.”

“Or Jesuit’s bark.”

“Which I haven’t seen in six months.” The surgeon still stood at the door. “Must I insist you leave, Major? God spare us a contagion.”

“Yes.” Sharpe knew he would never forgive himself if he did not give Hogan some gesture of friendship, however useless, so he stooped and took the sick man’s hand and gave it a gentle squeeze.

“Maquereau,” Hogan said quite distinctly.

“Maquereau?”

“Major!”

Sharpe obeyed the surgeon’s voice. “Does maquereau mean anything to you?”

“It’s a fish. The mackerel. It’s also French slang for pimp, Major. I told you, his wits are wandering.” The surgeon closed the door on the sickroom. “And one other piece of advice, Major.”

“Yes?”

“If you want your wife to live, then tell her she must stop visiting Colonel Hogan.”

Sharpe paused by his damp luggage. “Jane visits him?”

“A Mrs Sharpe visits daily/ the doctor said, ”but I have not the intimacy of her first name. Good day to you, Major.“

It was winter in France.

The floor was a polished expanse of boxwood, the walls were cliffs of shining marble, and the ceiling a riot of ornate plasterwork and paint. In the very centre of the floor, beneath the dark, cobweb encrusted chandelier and dwarfed by the huge proportions of the vast room, was a malachite table. Six candles, their light too feeble to reach into the corners of the great room, illuminated maps spread on the green stone table.

A man walked from the table to a fire that burned in an intricately carved hearth. He stared at the flames and, when at last he spoke, the marble walls made his voice seem hollow with despair. “There are no reserves.”

“Calvet’s demi-brigade…”

“Is ordered south without delay.” The man turned from the fire to look at the table where the candle-glow illuminated two pale faces above dark uniforms. “The Emperor will not take it kindly if we…”

“The Emperor,” the smallest man at the table interrupted in a voice of surprising harshness, “rewards success.”

January rain spattered the tall, east-facing windows. The velvet curtains of this room had been pulled down twenty-one years before, trophies to a revolutionary mob that had stormed triumphant through the streets of Bordeaux, and there had never been the money nor the will to hang new curtains. The consequence, in winters like this, was a draught of malevolent force. The fire scarcely warmed the hearth, let alone the whole huge room, and the general standing before the feeble flames shivered. “East or north.”