“You are the captain of this ship?” The Englishman’s eyes were red-rimmed from tiredness, but he picked Raines from the crowd of grim-faced hands at a glance. “I am acting captain Thomas Leonard, of His Majesty’s ship Porpoise. For the love of God,” he said, speaking hoarsely, “have you a surgeon aboard?”

Over a warily offered glass of port below, Captain Leonard explained that the Porpoise had suffered an outbreak of some infectious plague, beginning some four weeks before.

“Half the crew are down with it,” he said, wiping a crimson drop from his stubbled chin. “We’ve lost thirty men so far, and look fair to lose a lot more.”

“You lost your captain?” Raines asked.

Leonard’s thin face flushed slightly. “The—the captain and the two senior lieutenants died last week, and the surgeon and the surgeon’s mate, as well. I was third lieutenant.” That explained both his surprising youth and his nervous state; to be landed suddenly in sole command of a large ship, a crew of six hundred men, and a rampant infection aboard, was enough to rattle anyone.

“If you have anyone aboard with some medical experience…” He looked hopefully from Captain Raines to Jamie, who stood by the desk, frowning slightly.

“I’m the Artemis’s surgeon, Captain Leonard,” I said, from my place in the doorway. “What symptoms do your men have?”

“You?” The young captain’s head swiveled to stare at me. His jaw hung slackly open, showing the furred tongue and stained teeth of a tobacco-chewer.

“My wife’s a rare healer, Captain,” Jamie said mildly. “If it’s help ye came for, I’d advise ye to answer her questions, and do as she tells ye.”

Leonard blinked once, but then took a deep breath and nodded. “Yes. Well, it seems to start with griping pains in the belly, and a terrible flux and vomiting. The afflicted men complain of headache, and they have considerable fever. They…”

“Do some of them have a rash on their bellies?” I interrupted.

He nodded eagerly. “They do. And some of them bleed from the arse as well. Oh, I beg pardon, ma’am,” he said, suddenly flustered. “I meant no offense, only that—”

“I think I know what that might be,” I interrupted his apologies. A feeling of excitement began to grow in me; the feeling of a diagnosis just under my hands, and the sure knowledge of how to proceed with it. The call of trumpets to a warhorse, I thought with wry amusement. “I’d need to look at them, to be sure, but—”

“My wife would be pleased to advise ye, Captain,” Jamie said firmly. “But I’m afraid she canna go aboard your ship.”

“Are you sure?” Captain Leonard looked from one to the other of us, eyes desperate with disappointment. “If she could only look at my crew…”

“No,” Jamie said, at the same moment I replied, “Yes, of course!”

There was an awkward silence for a moment. Then Jamie rose to his feet, said politely, “You’ll excuse us, Captain Leonard?” and dragged me bodily out of the cabin, down the passage to the afterhold.

“Are ye daft?” he hissed, still clutching me by one arm. “Ye canna be thinking of setting foot on a ship wi’ the plague! Risk your life and the crew and Young Ian, all for the sake of a pack of Englishmen?”

“It isn’t plague,” I said, struggling to get free. “And I wouldn’t be risking my life. Let go of my arm, you bloody Scot!”

He let go, but stood blocking the ladder, glowering at me.

“Listen,” I said, striving for patience. “It isn’t plague; I’m almost sure it’s typhoid fever—the rash sounds like it. I can’t catch that, I’ve been vaccinated for it.”

Momentary doubt flitted across his face. Despite my explanations, he was still inclined to consider germs and vaccines in the same league with black magic.

“Aye?” he said skeptically. “Well, perhaps that’s so, but still…”

“Look,” I said, groping for words. “I’m a doctor. They’re sick, and I can do something about it. I…it’s…well, I have to, that’s all!”

Judging from its effect, this statement appeared to lack something in eloquence. Jamie raised one eyebrow, inviting me to go on.

I took a deep breath. How should I explain it—the need to touch, the compulsion to heal? In his own way, Frank had understood. Surely there was a way to make it clear to Jamie.

“I took an oath,” I said. “When I became a physician.”

Both eyebrows went up. “An oath?” he echoed. “What sort of oath?”

I had said it aloud only the one time. Still, I had had a framed copy in my office; Frank had given it to me, a gift when I graduated from medical school. I swallowed a small thickening in my throat, closed my eyes, and read what I could remember from the scroll before my mind’s eye.

“I swear by Apollo the physician, by Aesculapius, Hygeia, and Panacea, and I take to witness all the gods, all the goddesses, to keep according to my ability and my judgment the following Oath:

I will prescribe regimen for the good of my patients according to my ability and my judgment and never do harm to anyone. To please no one will I prescribe a deadly drug, nor give advice which may cause his death. But I will preserve the purity of my life and my art. In every house where I come I will enter only for the good of my patients, keeping myself far from all intentional ill-doing and all seduction, and especially from the pleasures of love with women or with men, be they free or slaves. All that may come to my knowledge in the exercise of my profession or outside of my profession or in daily commerce with men, which ought not to be spread abroad, I will keep secret and will never reveal. If I keep this oath faithfully, may I enjoy my life and practice my art, respected by all men and in all times; but if I swerve from it or violate it, may the reverse be my lot.”

I opened my eyes, to find him looking down at me thoughtfully. “Er…parts of it are just for tradition,” I explained.

The corner of his mouth twitched slightly. “I see,” he said. “Well, the first part sounds a wee bit pagan, but I like the part about how ye willna seduce anyone.”

“I thought you’d like that one,” I said dryly. “Captain Leonard’s virtue is safe with me.”

He gave a small snort and leaned back against the ladder, running one hand slowly through his hair.

“Is that how it’s done, then, in the company of physicians?” he asked. “Ye hold yourself bound to help whoever calls for it, even an enemy?”

“It doesn’t make a great difference, you know, if they’re ill or hurt.” I looked up, searching his face for understanding.

“Aye, well,” he said slowly. “I’ve taken an oath now and then, myself—and none of them lightly.” He reached out and took my right hand, his fingers resting on my silver ring. “Some weigh heavier than others, though,” he said, watching my face in turn.

He was very close to me, the sun from the hatchway overhead striping the linen of his sleeve, the skin of his hand a deep ruddy bronze where it cradled my own white fingers, and the glinting silver of my wedding ring.

“It does,” I said softly, speaking to his thought. “You know it does.” I laid my other hand against his chest, its gold ring glowing in a bar of sunlight. “But where one vow can be kept, without damage to another…?”

He sighed, deeply enough to move the hand on my chest, then bent and kissed me, very gently.

“Aye, well, I wouldna have ye be forsworn,” he said, straightening up with a wry twist to his mouth. “You’re sure of this vaccination of yours? It does work?”

“It works,” I assured him.

“Perhaps I should go with ye,” he said, frowning slightly.

“You can’t—you haven’t been vaccinated, and typhoid’s awfully contagious.”

“You’re only thinking it’s typhoid, from what Leonard says,” he pointed out. “Ye dinna ken for sure that it’s that.”

“No,” I admitted. “But there’s only one way to find out.”

I was assisted up onto the deck of the Porpoise by means of a bosun’s chair, a terrorizing swing over empty air and frothing sea. I landed ignominiously in a sprawl on the deck. Once I regained my feet, I was astonished to find how solid the deck of the man-of-war felt, compared to the tiny, pitching quarterdeck of the Artemis, far below. It was like standing on the Rock of Gibraltar.

My hair had blown loose during the trip between the ships; I twisted it up and repinned it as best I could, then reached to take the medicine box I had brought from the midshipman who held it.

“You’d best show me where they are,” I said. The wind was brisk, and I was aware that it was taking a certain amount of work on the part of both crews to keep the two ships close together, even as both drifted leeward.

It was dark in the tween-decks, the confined space lit by small oil lamps that hung from the ceiling, swaying gently with the rise and fall of the ship, so that the ranks of hammocked men lay in deep shadow, blotched with dim patches of light from above. They looked like pods of whales, or sleeping sea beasts, lying humped and black, side by side, swaying with the movement of the sea beneath.

The stench was overpowering. What air there was came down through crude ventilator shafts that reached the upper deck, but that wasn’t a lot. Worse than unwashed seamen was the reek of vomitus and the ripe, throat-clogging smell of blood-streaked diarrhea, which liberally spattered the decking beneath the hammocks, where sufferers had been too ill to reach the few available chamber pots. My shoes stuck to the deck, coming away with a nasty sucking noise as I made my way cautiously into the area.

“Give me a better light,” I said peremptorily to the apprehensive-looking young midshipman who had been told off to accompany me. He was holding a kerchief to his face and looked both scared and miserable, but he obeyed, holding up the lantern he carried so that I could peer into the nearest hammock.

The occupant groaned and turned away his face as the light struck him. He was flushed with fever, and his skin hot to the touch. I pulled his shirt up and felt his stomach; it too was hot, the skin distended and hard. As I prodded gently here and there, the man writhed like a worm on a hook, uttering piteous groans.

“It’s all right,” I said soothingly, urging him to flatten out again. “Yes, I’ll help you; it will feel better soon. Let me look into your eyes, now. Yes, that’s right.”

I pulled back the eyelid; his pupil shrank in the light, leaving his eyes brown and red-rimmed with suffering.

“Christ, take away the light!” he gasped, jerking his head away. “It splits my head!” Fever, vomiting, abdominal cramps, headache.

“Do you have chills?” I asked, waving back the midshipman’s lantern.

The answer was more a moan than a word, but in the affirmative. Even in the shadows, I could see that many of the men in the hammocks were wrapped in their blankets, though it was stifling hot here below.