The man who arrived on the heighliner's last shuttle did not look like an off-worlder accustomed to wealth. He wore a dark traveling coat unsuited to the heat, carried a single battered case, and observed the spaceport of Arrakeen with eyes that seemed to catalogue every grain of sand.
Duke Leto Atreides received him in the great hall, where the bull's head of his father still glowered from the wall. "You come highly recommended, Mr. Holmes. Though I confess I do not understand how a man from a backwater of the Imperium earned such reputation."
"Reputation is merely the residue of observation, Your Grace," said Sherlock Holmes. "For instance, I observe that your Mentat standing in the shadow to my left has consumed sapho juice within the hour — the stain upon his lips — and that he distrusts me intensely, judging by the angle of his stance. I observe also that you have not slept. The death of your councilor weighs upon you more than you wish your court to know."
Thurir Hawat stepped forward, eyes narrowing. "My lord, this is theatrics. A Mentat computes; we do not require a stranger's parlor tricks."
"And yet," Holmes replied mildly, "your computations have, in three days, produced no murderer. Perhaps theatrics and truth are not so distant as you imagine."
Leto raised a hand. "Enough. The facts, gentlemen. Councilor Vannic was found dead in his private study. The door was bolted from within. The window — there is no window; the chamber is sealed against the desert. There was no wound upon him, no poison detected by our snoopers, no sign of struggle. My physician calls it heart failure. Hawat does not believe it. Neither do I."
"Why not?" asked Holmes.
"Because Vannic knew something," said Leto quietly. "He had requested an audience for the morning he died. He said he had discovered a traitor among us."
Holmes's eyes brightened, the dullness of travel falling away like a shed cloak. "Then we begin with the room. Show me the room."
The study was small, austere, lined with shigawire spools and a single chair behind a stone desk. The air smelled faintly of cinnamon — the omnipresent breath of melange that hung over all of Arrakis. Holmes paused at the threshold and would not let the others enter.
"Stand back. You have all trampled this floor like cattle already, I see, but I shall salvage what remains." He sank to his knees, producing a small brass lens from his coat. He crawled the perimeter of the chamber with terrible patience, murmuring to himself.
"The door bolted from within," he said. "The bolt is heavy, iron, undisturbed. The walls are solid rock, the ceiling sealed. And yet a man is dead by no natural cause. The locked room, gentlemen, is the oldest riddle and the most foolish. There is always a way in. The question is whether the killer entered the room — or whether death entered without him."
"Riddles," muttered Hawat.
Holmes lifted a small object from the floor near the desk — so small the Mentat had to squint. It was a fragment of something brittle and translucent, like a sliver of glass, no larger than a fingernail clipping.
"What is this?" Holmes asked. "Hawat. You are a Mentat. You know the textures of this world better than I. Tell me what I hold."
Hawat approached, took it, and his weathered face went still. "Chitin," he said slowly. "Insect chitin. But there are no insects on Arrakis save —"
"Save?"
"There are tales. Hunter-seekers fashioned in the old style. And there are the desert's own small horrors. But this is neither." He turned the fragment in the light. "This is the casing of a drug-needle. The kind smugglers grow from cultured beetles on Giedi Prime. A Harkonnen device."
Holmes took back the fragment and regarded it with something like affection. "Excellent. You are useful after all, Mentat. Now. A needle of cultured chitin would carry a poison that the body absorbs and renders down, leaving no trace for your snoopers — for your snoopers hunt for foreign chemicals, not for the body's own substances turned against it. Tell me, where was the councilor sitting when found?"
"In his chair," said Leto. "Slumped over the desk."
Holmes seated himself in the chair, folding his long frame into it, and looked about with the eyes of a dead man. He looked up. Above the desk, set into the stone ceiling, was the dark circular grille of an air-reclamation vent — part of the windtrap system that kept the chamber breathable and conserved its moisture, as all things on Arrakis conserved moisture.
"The vent," he said. "Bring a ladder."
Within the vent, where no servant cleaned and no Mentat had thought to look, Holmes found the device: a small mechanism of dark metal and grown chitin, clamped to the inside of the ducting, its needle-barrel now empty.
"A clever instrument," he said, lowering himself down with the thing cradled in a kerchief. "It waits. It listens, perhaps, for a voice signature, or simply for the heat of a body settling beneath it for a length of time. Then it fires a single dart, too fine to feel, into the scalp or the neck. The dart dissolves. The poison mimics cardiac arrest. The councilor dies alone in a locked room, and a dozen wise men conclude he died of natural causes — all but one." He inclined his head toward Hawat. "And one who merely suspected, without proof."
Leto's face had gone hard as the rock walls. "Then it is the Harkonnens. As we always knew it would be. The Baron reaches even into my house."
"Patience, Your Grace." Holmes lifted a long finger. "The instrument is of Harkonnen manufacture. That tells us where it was made. It does not tell us whose hand placed it in that vent. A weapon is bought and sold. The interesting question — the only question — is how it came to be installed in a chamber within your own keep, past your guards, your shields, your loyal Mentat's vigilance. That, Your Grace, was no act of the Baron. It was the act of someone who walks these halls and bows when you pass."
Silence fell. Hawat's hand drifted near his weapon.
"A traitor," Leto whispered. "Vannic was right."
"Vannic was right, and Vannic was killed for being right, and the manner of his killing was chosen precisely so that no one would believe him even in death." Holmes rose and began to pace, his coat sweeping the dust. "Now I require facts, and many of them, and I require them quickly. Who knew that Vannic had requested his audience?"
It was Hawat who answered, the Mentat's recall flawless. "The request passed through three hands. Vannic's own. Mine — I logged it. And the household chamberlain, Sufrin, who arranges the Duke's calendar."
"And who has access to the air-reclamation systems? Who might enter a vent unremarked?"
"The water-engineers," said Leto. "The Fremen we have hired to maintain the windtraps. And the maintenance staff of the keep."
Holmes stopped. "Show me Vannic's hands."
They brought him to the cold chamber where the body lay wrapped in a stillsuit, for even the dead surrendered their water to the household on Arrakis. Holmes drew back the covering and examined the councilor's fingers with his lens.
"Ink," he said. "Beneath the nail of the right forefinger. Old-fashioned ink, the sort used to write where electronic records might be intercepted. Your councilor did not trust your own communication systems, Your Grace. A wise man. He wrote something by hand and hid it. Where did he sleep?"
Vannic's bedchamber yielded nothing to the others, but Holmes spent an hour upon his knees once more, tapping at the floor stones, the walls, the frame of the cot. At last he paused beside the small water-shrine that every dwelling on Arrakis kept — a reservoir of the household's precious moisture, sealed and revered.
"A man hides what he treasures where treasure is already guarded," Holmes murmured. He pressed the rim of the shrine, found the false seam his fingers had been hunting, and withdrew a thin roll of spice-paper.
The writing was cramped, hurried. Leto read it aloud, his voice tightening with each line.
"'The diversion of spice from the southern harvest is no error of bookkeeping. The figures are altered after they leave the field-Mentat and before they reach Hawat's audit. Only one office stands between. The Baron's gold buys the pen of the man who keeps the Duke's hours. I will tell the Duke at dawn. If I do not — '" Leto stopped. "It ends there."
"The man who keeps the Duke's hours," Holmes repeated softly. "Your chamberlain. Sufrin."
Hawat's breath hissed. "It cannot be. Sufrin has served the household twenty years. I vetted him myself. I have examined his accounts, his contacts, his every —"
"And found nothing, because a man who has decided to betray and waited twenty years to do it leaves nothing to find," said Holmes. "Loyalty is the perfect disguise, Mentat, because it is the one thing you do not think to suspect. But let us not condemn on the word of a dead man alone. Vannic accuses; the dead may be mistaken, or may be made to seem to accuse. We will test it. Where is Sufrin now?"
"Awaiting the Duke's pleasure in the antechamber," said Hawat. "As he does each evening."
"Then bring him to Vannic's study. And bring the device — but let me hold it. And say nothing of the paper."
In the dead councilor's study, the chamberlain Sufrin came as summoned — a soft-spoken man with mild eyes and the stooped attentiveness of one who has spent a lifetime anticipating the wants of greater men. He bowed low.
"Your Grace. How may I serve?"
Holmes spoke before the Duke could. "Sufrin. We have solved the riddle of the councilor's death. He was murdered — by a device installed in that vent." He pointed upward. "A clever Harkonnen instrument. We have recovered it intact." He opened his hand to reveal the dark mechanism. "And being intact, it retains within its memory-cell the imprint of the last hand to arm it. We need only read it."
It was a lie, of course. The device held no such record; Holmes had invented it from whole cloth. But he watched Sufrin's face as a falconer watches the sky.
The chamberlain's mild eyes flicked — only for an instant — to the vent above the desk. Not to the device in Holmes's hand. To the vent. To the place where it had been hidden. To the one location only the installer could know mattered.
"A terrible thing," Sufrin murmured. "The Baron's reach is long."
"It is," Holmes agreed pleasantly. "Tell me, Sufrin — how did you know to look up?"
The chamberlain went very still.
"I told you the device was in a vent," said Holmes. "I did not tell you which. This study has three air channels; the others are in the floor and the eastern wall. Yet your eyes went directly to the ceiling above the desk — to the precise vent, the only one positioned to fire upon a seated man. A guilty memory, Sufrin, is the one witness that cannot be bribed."
Sufrin's hand moved toward his sleeve. Hawat was faster; the Mentat had the man's wrist twisted behind him before the hidden blade cleared its sheath. A small dart-pistol clattered to the stone floor — the twin, surely, of the instrument that had killed Vannic.
"Twenty years," Leto said, and there was more grief than anger in it. "Why?"
Sufrin's mild mask had cracked, and what showed beneath was older and colder. "Because you were always going to lose, Atreides," he spat. "The Emperor fears your name. The Baron wants your spice. You were given Arrakis as a man is given a beautiful poison. I merely chose to survive the drinking of it. Vannic would have warned you. I could not allow him to delay the inevitable."
"Take him," said Leto, and the guards came.
When the chamber had emptied, the Duke turned to Holmes. "You have done in an afternoon what my Mentat could not do in three days. Name your reward."
"I have already received it," said Holmes. "A genuine problem. They are rarer than spice and worth a great deal more to me." He paused at the door. "But I will offer you something freely, Your Grace, for I find I have come to respect this house. Sufrin spoke truly in one respect. You have been handed a poison. The Harkonnens did not need a chamberlain merely to skim spice; they needed eyes within your walls for a greater blow yet to fall. I would urge your Mentat to assume that every loyalty has been tested, and to trust the cold logic of evidence over the warm comfort of long acquaintance. The most dangerous traitor is not the one who hates you. It is the one who has served you so faithfully that you cannot imagine the knife in his hand."
Hawat, who had not spoken, inclined his head — the smallest of bows, but from a Mentat to an off-worlder it was a thing rarely given. "You reason as we are trained to reason," he said. "And yet you reach where we cannot. How?"
Holmes smiled faintly. "You compute from the data you are given. I observe the data that no one thought worth giving. A fragment of chitin. Ink beneath a nail. The direction of a frightened man's glance. The world is drowning in such trifles, Mentat, and they are the only honest witnesses we have. Everything else lies."
He stepped out into the warm desert night, where the first stars of Arrakis burned hard and clear above the dunes, and the wind carried up from the deep waste the faint, ceaseless scent of cinnamon — the breath of the great worms, and of the spice, and of all the vast machinery of murder and empire that turned upon this single golden grain. Somewhere out there, Holmes reflected, a debt had been postponed but not paid. The game, as ever, was only beginning.
Behind him, Duke Leto Atreides looked up at the open vent in his dead councilor's study and understood, perhaps for the first time fully, exactly what kind of trap he had been led into — and resolved, with cold and quiet fury, to be the hunter Sufrin's masters had never expected him to become.