“Richard,” Steinhaueser had said, “it’s as insidious as opium and almost as addictive. You don’t know what it might be costing you. What if it permanently damages your senses? Avoid. Avoid at all cost.”

But Saltzmann’s Tincture had cured Burton of the various ailments he’d brought back from India, saved him from blindness during his pilgrimage to Mecca, kept malaria at bay throughout his ill-fated penetration of Berbera, and had—despite Sister Raghavendra’s seconding of Steinhaueser’s opinion—sustained him while he led the search for the source of the Nile. For sure, in the final days of the expedition, he’d succumbed to the fever that was currently burning through his veins, but it wasn’t half as bad as those experienced by the members of the Royal Geographical Society who scorned Saltzmann’s and relied, instead, upon quinine. Livingstone, for example, was very vocal in his opposition to it and suffered as a consequence. In his most recent dispatch, sent from a village near the headwaters of the Congo and received at Zanzibar four years ago, Livingstone had reported himself “terribly knocked up” and predicted that he’d never see civilisation again. If only I had my faith to sustain me, he’d written, but the terrible things I have witnessed in these wicked lands have stripped it from me. I am no better than a beast. He hadn’t been heard from since, and was now presumed dead.

Saltzmann’s. If Livingstone had taken Saltzmann’s, he’d have maintained his health and seen a way out of whatever predicament he was in.

Burton broke the bottle’s seal, popped out the cork, hesitated a moment, then drank half of the clear, syrupy contents. Moments later, a delicious warmth chased the ache from his joints.

He turned and lurched across the room to the door, lifted his jubbah—the loose robe he’d worn during his pilgrimage—down from a hook, wrapped it around himself, then pushed his feet into Arabian slippers.

A walking cane caught his eye. It was leaning against the wall. Its silver grip had been fashioned into the shape of a panther’s head. He picked it up and realised it concealed a blade, which he drew and examined: an extremely well-balanced rapier.

Sheathing the weapon and using it for support, the explorer opened the door and stepped out into the passageway beyond, finding it warmly illuminated by bracket-mounted oil lamps. His cabin was on the lower of the Orpheus’s two decks, in the middle of the mostly unoccupied rear passenger section. William Stroyan’s was a little farther along, closer to the stern observation room. He hobbled toward it. The corridor wavered around him like a mirage, and for a moment, he thought himself trekking across African savannah. He shook off the delusion and whispered, “Fool. You can barely stay upright. Why can’t you just leave it be?”

He came to Stroyan’s cabin and found its door standing partially open.

“Bill?”

No reply.

He rapped his knuckles against it.

“I say! Stroyan?”

Nothing.

He pushed the door open and entered. The lieutenant’s bed was unmade, the room empty and lit only by starlight glimmering through the porthole.

Burton noticed his friend’s pocket watch on the bedside table. He picked it up and angled its face to the light from the passage. Eight minutes to midnight.

Perhaps Stroyan was having trouble sleeping and had left this quiet area of the vessel to join the crew on the upper deck.

No. The bedsheets. The lieutenant is as neat as they come. Army training. He’d never leave his bedding twisted and trailing off the bunk like that.

And—

Burton grunted, took a box of lucifers from the table, lit one, and applied the spitting, sulphurous flame to a lamp, which he then lowered over the thing he’d noticed on the floor.

A pillow, darkly stained.

Blood.

He straightened, looked around again, saw the speaking tube, crossed to it, whistled into the mouthpiece, then put it to his ear and waited for a response.

A tinny voice said, “Yes, Lieutenant? What can I do for you?”

It was Doctor Quaint, the ship’s steward and surgeon.

“It’s not Stroyan, Doctor. It’s Burton.”

“Good Lord! I thought you were incapacitated.”

“Not quite. Do you know where Stroyan is?”

“I haven’t seen him since dinner, sir.”

“I think someone struck him on the head and dragged him from his bed. Would you have the captain come down here, please?”

“Struck? Bed? Are you—?”

“I’m not delirious, I can assure you. Will you—”

“The captain. I’ll tell him at once, sir.”

“Thank you.”

As he returned the speaking tube to its housing, the muted chanting touched his senses again. He cocked his head and listened. It was louder now, a single voice, generally low and rhythmic but occasionally increasing in volume, as if impassioned and unable to fully contain itself.

Curiosity got the better of him, turned him around, and drew him back out into the passage. His balance was off and he stumbled along as if drunk, but pushed himself onward, spurred by a growing impatience with his own weakness and an almost vicious determination to conquer it and discover the origin of the mysterious sounds.

As he passed the passenger cabin doors, each summoned a splintered recollection, as if they opened onto memories rather than empty chambers.

Number 35: Lieutenant George Herne. Like Burton, down with fever. He’d been left at Zanzibar, where, when he recovered, he’d be taking over as the island’s new consul. Burton would miss him. Herne was a good sort. A little stolid and unimaginative, perhaps, but loyal. Unflappable.

Number 36: Gordon Champion. The airship’s chief rigger. Dead. He’d crawled out along one of the engine pylons to investigate the inexplicable power failure that had immobilised the vessel just north of Africa’s Central Lakes. He’d lost his footing. The slightest of misjudgments and—snap!—gone. That’s how quickly, easily, and apparently randomly a life could be extinguished.

Number 37: John Hanning Speke. A beetle had crawled into his ear and he’d permanently deafened himself while trying to extract it with hot wax and a penknife.

What?

No.

There was no door 37.

That last never happened.

Burton reeled as a wave of dizziness hit him. He slapped a hand against the wall and rested for a moment. Why did he keep thinking about Speke? He’d hardly known the man.

This was a mistake. He should get back to bed. He was beginning to hallucinate again. He could see Speke’s face as clear as day, the lieutenant’s pale blue right eye contrasting starkly with the dark lens of his mechanical left.

Except Speke never had a mechanical left eye.

What is happening to me?

A voice pulled him back into reality. He looked up. The double doors to the observation deck were just ahead. The chanting was coming from behind them. It had just risen in pitch.

He wiped sweat from his eyes, closed them, and concentrated on the sweet tingle of the Saltzmann’s Tincture as it oozed honey-like through his arteries. He felt it climbing his neck and easing into the back of his skull.

I’ve made history.

He would be accepted; offered an official position; hopefully, like Herne, a consulship. Damascus. He could marry Isabel and settle there; start his translation of A Thousand Nights and a Night. No one would again accuse him of being “un-English.” No one would dare to call him “Blackguard Burton” or “Ruffian Dick.” His years of exclusion and exile were over.

He tottered forward, holding tightly to the swordstick.

The chanting had greater clarity now. A man, repeating the same phrase over and over. Burton was an accomplished linguist, fluent in nearly thirty languages, but the incantation was utterly unfamiliar; a pulsating jumble of outlandish sounds and syllables, unfathomable, even to him.