As the ruler of Ptarth, followed by his courtiers,descended from the landing-stage above the palace,the servants dropped into their places in the rearof their royal or noble masters, and behind the othersone lingered to the last. Then quickly stoopinghe snatched the sandal from his right foot, slippingit into his pocket-pouch.

When the party had come to the lower levels, and thejeddak had dispersed them by a sign, none noticed thatthe forward fellow who had drawn so much attention tohimself before the Prince of Helium departed, was nolonger among the other servants.

To whose retinue he had been attached none had thoughtto inquire, for the followers of a Martian nobleare many, coming and going at the whim of their master,so that a new face is scarcely ever questioned, as thefact that a man has passed within the palace walls isconsidered proof positive that his loyalty to the jeddakis beyond question, so rigid is the examination of eachwho seeks service with the nobles of the court.

A good rule that, and only relaxed by courtesy in favour ofthe retinue of visiting royalty from a friendly foreign power.

It was late in the morning of the next day that a giantserving man in the harness of the house of a great Ptarthnoble passed out into the city from the palace gates.Along one broad avenue and then another he strode brisklyuntil he had passed beyond the district of the nobles andhad come to the place of shops. Here he sought a pretentiousbuilding that rose spire-like toward the heavens, its outer wallselaborately wrought with delicate carvings and intricate mosaics.

It was the Palace of Peace in which were housed therepresentatives of the foreign powers, or rather inwhich were located their embassies; for the ministersthemselves dwelt in gorgeous palaces within the districtoccupied by the nobles.

Here the man sought the embassy of Dusar. A clerkarose questioningly as he entered, and at his requestto have a word with the minister asked his credentials.The visitor slipped a plain metal armlet from above his elbow,and pointing to an inscription upon its inner surface,whispered a word or two to the clerk.

The latter's eyes went wide, and his attitude turned atonce to one of deference. He bowed the stranger to a seat,and hastened to an inner room with the armlet in his hand.A moment later he reappeared and conducted the caller intothe presence of the minister.

For a long time the two were closeted together, and when atlast the giant serving man emerged from the inner office hisexpression was cast in a smile of sinister satisfaction.From the Palace of Peace he hurried directly to the palaceof the Dusarian minister.

That night two swift fliers left the same palace top. One sped its rapid course toward Helium; the other--

Thuvia of Ptarth strolled in the gardens of her father's palace,as was her nightly custom before retiring. Her silks and furswere drawn about her, for the air of Mars is chill after thesun has taken his quick plunge beneath the planet's western verge.

The girl's thoughts wandered from her impending nuptials, that wouldmake her empress of Kaol, to the person of the trim young Heliumitewho had laid his heart at her feet the preceding day.

Whether it was pity or regret that saddened her expressionas she gazed toward the southern heavens where she hadwatched the lights of his flier disappear the previous night,it would be difficult to say.

So, too, is it impossible to conjecture just what heremotions may have been as she discerned the lights ofa flier speeding rapidly out of the distance from thatvery direction, as though impelled toward her gardenby the very intensity of the princess' thoughts.

She saw it circle lower above the palace until she waspositive that it but hovered in preparation for a landing.

Presently the powerful rays of its searchlight shot downwardfrom the bow. They fell upon the landing-stage for a briefinstant, revealing the figures of the Ptarthian guard,picking into brilliant points of fire the gems upon theirgorgeous harnesses.

Then the blazing eye swept onward across the burnisheddomes and graceful minarets, down into court and parkand garden to pause at last upon the ersite bench andthe girl standing there beside it, her face upturned fulltoward the flier.

For but an instant the searchlight halted upon Thuviaof Ptarth, then it was extinguished as suddenly as it hadcome to life. The flier passed on above her to disappearbeyond a grove of lofty skeel trees that grew within thepalace grounds.

The girl stood for some time as it had left her, exceptthat her head was bent and her eyes downcast in thought.

Who but Carthoris could it have been? She tried to feelanger that he should have returned thus, spying upon her;but she found it difficult to be angry with the youngprince of Helium.

What mad caprice could have induced him so to transgressthe etiquette of nations? For lesser things great powershad gone to war.

The princess in her was shocked and angered--but what of the girl!

And the guard--what of them? Evidently they, too,had been so much surprised by the unprecedented actionof the stranger that they had not even challenged;but that they had no thought to let the thing go unnoticedwas quickly evidenced by the skirring of motors uponthe landing-stage and the quick shooting airward of along-lined patrol boat.

Thuvia watched it dart swiftly eastward. So, too,did other eyes watch.

Within the dense shadows of the skeel grove, in awide avenue beneath o'erspreading foliage, a flier hung adozen feet above the ground. From its deck keen eyeswatched the far-fanning searchlight of the patrol boat. No light shone from the enshadowed craft. Upon its deckwas the silence of the tomb. Its crew of a half-dozen redwarriors watched the lights of the patrol boat diminishingin the distance.

"The intellects of our ancestors are with us to-night,"said one in a low tone.

"No plan ever carried better," returned another. "Theydid precisely as the prince foretold."

He who had first spoken turned toward the man whosquatted before the control board.

"Now!" he whispered. There was no other order given. Every man upon the craft had evidently been well schooledin each detail of that night's work. Silently the dark hullcrept beneath the cathedral arches of the dark and silent grove.

Thuvia of Ptarth, gazing toward the east, saw the blacker blotagainst the blackness of the trees as the craft topped thebuttressed garden wall. She saw the dim bulk incline gentlydownward toward the scarlet sward of the garden.

She knew that men came not thus with honourable intent. Yet she did not cry aloud to alarm the near-by guardsmen,nor did she flee to the safety of the palace.

Why?

I can see her shrug her shapely shoulders in reply as shevoices the age-old, universal answer of the woman: Because!

Scarce had the flier touched the ground when four menleaped from its deck. They ran forward toward the girl.

Still she made no sign of alarm, standing as though hypnotized.Or could it have been as one who awaited a welcome visitor?

Not until they were quite close to her did she move. Then the nearer moon, rising above the surrounding foliage,touched their faces, lighting all with the brilliancy of her silver rays.

Thuvia of Ptarth saw only strangers--warriors in theharness of Dusar. Now she took fright, but too late!

Before she could voice but a single cry, rough handsseized her. A heavy silken scarf was wound about herhead. She was lifted in strong arms and borne to the deckof the flier. There was the sudden whirl of propellers, therushing of air against her body, and, from far beneath theshouting and the challenge from the guard.

Racing toward the south another flier sped toward Helium.In its cabin a tall red man bent over the soft sole of anupturned sandal. With delicate instruments he measuredthe faint imprint of a small object which appeared there.Upon a pad beside him was the outline of a key,and here he noted the results of his measurements.

A smile played upon his lips as he completed his task andturned to one who waited at the opposite side of the table.

"The man is a genius," he remarked.

"Only a genius could have evolved such a lock as thisis designed to spring. Here, take the sketch, Larok, andgive all thine own genius full and unfettered freedomin reproducing it in metal."

The warrior-artificer bowed. "Man builds naught,"he said, "that man may not destroy." Then he left thecabin with the sketch.

As dawn broke upon the lofty towers which mark the twin citiesof Helium--the scarlet tower of one and the yellow tower ofits sister--a flier floated lazily out of the north.

Upon its bow was emblazoned the signia of a lesser nobleof a far city of the empire of Helium. Its leisurelyapproach and the evident confidence with which it movedacross the city aroused no suspicion in the minds of thesleepy guard. Their round of duty nearly done, they had littlethought beyond the coming of those who were to relieve them.

Peace reigned throughout Helium. Stagnant, emasculatingpeace. Helium had no enemies. There was naught to fear.

Without haste the nearest air patrol swung sluggishlyabout and approached the stranger. At easy speakingdistance the officer upon her deck hailed the incoming craft.

The cheery "Kaor!" and the plausible explanation that theowner had come from distant parts for a few days of pleasurein gay Helium sufficed. The air-patrol boat sheered off,passing again upon its way. The stranger continued towarda public landing-stage, where she dropped into the waysand came to rest.

At about the same time a warrior entered her cabin.

"It is done, Vas Kor," he said, handing a small metalkey to the tall noble who had just risen from his sleepingsilks and furs.

"Good!" exclaimed the latter. "You must have workedupon it all during the night, Larok."

The warrior nodded.

"Now fetch me the Heliumetic metal you wrought somedays since," commanded Vas Kor.

This done, the warrior assisted his master to replacethe handsome jewelled metal of his harness with theplainer ornaments of an ordinary fighting man of Helium,and with the insignia of the same house that appearedupon the bow of the flier.

Vas Kor breakfasted on board. Then he emerged uponthe aerial dock, entered an elevator, and was borne quicklyto the street below, where he was soon engulfed by the earlymorning throng of workers hastening to their daily duties.

Among them his warrior trappings were no more remarkablethan is a pair of trousers upon Broadway. All Martian menare warriors, save those physically unable to bear arms. The tradesman and his clerk clank with their martialtrappings as they pursue their vocations. The schoolboy,coming into the world, as he does, almost adult from thesnowy shell that has encompassed his development for fivelong years, knows so little of life without a sword at hiship that he would feel the same discomfiture at going abroadunarmed that an Earth boy would experience in walking thestreets knicker-bockerless.

Vas Kor's destination lay in Greater Helium, which liessome seventy-five miles across the level plain from LesserHelium. He had landed at the latter city because the airpatrol is less suspicious and alert than that above thelarger metropolis where lies the palace of the jeddak.

As he moved with the throng in the parklike canyon ofthe thoroughfare the life of an awakening Martian citywas in evidence about him. Houses, raised high upon theirslender metal columns for the night were dropping gentlytoward the ground. Among the flowers upon the scarlet swardwhich lies about the buildings children were already playing,and comely women laughing and chatting with their neighbours asthey culled gorgeous blossoms for the vases within doors.

The pleasant "kaor" of the Barsoomian greeting fellcontinually upon the ears of the stranger as friends andneighbours took up the duties of a new day.

The district in which he had landed was residential--adistrict of merchants of the more prosperous sort. Everywhere were evidences of luxury and wealth.Slaves appeared upon every housetop with gorgeous silksand costly furs, laying them in the sun for airing. Jewel-encrusted women lolled even thus early upon the carvenbalconies before their sleeping apartments. Later in the daythey would repair to the roofs when the slaves had arrangedcouches and pitched silken canopies to shade them from the sun.

Strains of inspiring music broke pleasantly from open windows,for the Martians have solved the problem of attuning thenerves pleasantly to the sudden transition from sleep towaking that proves so difficult a thing for most Earth folk.

Above him raced the long, light passenger fliers, plying,each in its proper plane, between the numerous landing-stages for internal passenger traffic. Landing-stages thattower high into the heavens are for the great internationalpassenger liners. Freighters have other landing-stages atvarious lower levels, to within a couple of hundred feetof the ground; nor dare any flier rise or drop from oneplane to another except in certain restricted districts wherehorizontal traffic is forbidden.

Along the close-cropped sward which paves the avenue groundfliers were moving in continuous lines in opposite directions.For the greater part they skimmed along the surface of the sward,soaring gracefully into the air at times to pass over aslower-going driver ahead, or at intersections, where thenorth and south traffic has the right of way and the eastand west must rise above it.

From private hangars upon many a roof top fliers weredarting into the line of traffic. Gay farewells and partingadmonitions mingled with the whirring of motors andthe subdued noises of the city.

Yet with all the swift movement and the countlessthousands rushing hither and thither, the predominantsuggestion was that of luxurious ease and soft noiselessness.

Martians dislike harsh, discordant clamour. The onlyloud noises they can abide are the martial sounds of war,the clash of arms, the collision of two mighty dreadnoughtsof the air. To them there is no sweeter music than this.

At the intersection of two broad avenues Vas Kor descendedfrom the street level to one of the great pneumaticstations of the city. Here he paid before a little wicketthe fare to his destination with a couple of the dull,oval coins of Helium.

Beyond the gatekeeper he came to a slowly movingline of what to Earthly eyes would have appeared to beconical-nosed, eight-foot projectiles for some giant gun. In slow procession the things moved in single file alonga grooved track. A half dozen attendants assisted passengersto enter, or directed these carriers to their proper destination.

Vas Kor approached one that was empty. Upon its nose wasa dial and a pointer. He set the pointer for a certainstation in Greater Helium, raised the arched lid ofthe thing, stepped in and lay down upon the upholsteredbottom. An attendant closed the lid, which locked with alittle click, and the carrier continued its slow way.

Presently it switched itself automatically to another track,to enter, a moment later, one of the series of dark- mouthed tubes.

The instant that its entire length was within the blackaperture it sprang forward with the speed of a rifle ball. There was an instant of whizzing--a soft, though sudden,stop, and slowly the carrier emerged upon another platform,another attendant raised the lid and Vas Kor stepped out atthe station beneath the centre of Greater Helium,seventy-five miles from the point at which he had embarked.

Here he sought the street level, stepping immediatelyinto a waiting ground flier. He spoke no word to the slavesitting in the driver's seat. It was evident that he hadbeen expected, and that the fellow had received his instructionsbefore his coming.

Scarcely had Vas Kor taken his seat when the flierwent quickly into the fast-moving procession, turningpresently from the broad and crowded avenue into aless congested street. Presently it left the throngeddistrict behind to enter a section of small shops, where itstopped before the entrance to one which bore the signof a dealer in foreign silks.

Vas Kor entered the low-ceiling room. A man at thefar end motioned him toward an inner apartment, givingno further sign of recognition until he had passed inafter the caller and closed the door.

Then he faced his visitor, saluting deferentially.

"Most noble--" he commenced, but Vas Kor silencedhim with a gesture.

"No formalities," he said. "We must forget that Iam aught other than your slave. If all has been ascarefully carried out as it has been planned, we have notime to waste. Instead we should be upon our way to theslave market. Are you ready?"

The merchant nodded, and, turning to a great chest,produced the unemblazoned trappings of a slave. TheseVas Kor immediately donned. Then the two passed fromthe shop through a rear door, traversed a winding alleyto an avenue beyond, where they entered a flier whichawaited them.

Five minutes later the merchant was leading his slaveto the public market, where a great concourse of peoplefilled the great open space in the centre of which stoodthe slave block.

The crowds were enormous to-day, for Carthoris,Prince of Helium, was to be the principal bidder.

One by one the masters mounted the rostrum besidethe slave block upon which stood their chattels.Briefly and clearly each recounted the virtues ofhis particular offering.

When all were done, the major-domo of the Prince of Heliumrecalled to the block such as had favourably impressed him.For such he had made a fair offer.

There was little haggling as to price, and none at allwhen Vas Kor was placed upon the block. His merchant-master accepted the first offer that was made for him, andthus a Dusarian noble entered the household of Carthoris.