The Tower of Glass thrust up from the sea like a blade of ice, chill and deadly.

The planes of its four sides were formed of glass panels, level upon level, joined by a web of lines so fine that at a distance each wall became a single sheet of shining material. Like enormous mirrors they reflected the ocean and the sky about with a cold, detached precision.

In the slanting rays of the dawn sun, the eastern face was a painful glare of blue-white diamond light. It made the Tower seem all the more starkly alien, alone in that soft, sun-flecked expanse of level sea.

The soaring structure was set firmly in a base of smooth gray stone. And this foundation was itself imbedded deeply in an island of jagged rock barely larger than the Tower itself.

The base, like the glass walls above, was devoid of openings, save at one point. On the southern side, a knobby elbow of the island thrust into the sea, forming a sizeable cove. Here massive quays of the same smooth stone stretched far out into the waters of the cove. And here, in a line along the foundation wall, a dozen immense, square openings with heavy doors of a dull gray metal gave access to the Tower's interior.

At the quays were tied a score of slender ships of a curiously smooth, black metal. Men in close-fitting uniforms of silver-gray worked busily upon one of them, preparing it for sea and the arrival of a special passenger.

A flat, hollow tone, like the repeated note on some great horn, began to sound echoingly across the quays. It brought the attention of the working men to the base of the Tower. There, with a piercing, metallic squeal, one of the metal doors began to lift.

It rose slowly, as if with an effort, accompanied by a tremendous clattering. Beyond the growing opening only the blackness of the Tower's interior was revealed.

When the door had risen halfway, it clanged abruptly to a stop. From the darkness appeared a double column of men, clad in similar gray uniforms, but wearing helmets--smooth, rounded skullcaps of bright silver--and carrying strange devices like thick spears of metal, but tipped with balls of silver instead of points.

Twenty soldiers emerged from the Tower, moving in a brisk, high-stepping march. As the last moved onto the quay, they halted, and the two lines executed sharp turns to face one another. They stood, straight and motionless and identical, like chiseled granite figures lining some temple corridor.

The men on the ship now ceased their work to watch with open curiosity as a single figure appeared from the shadowed depths of the Tower and walked down the aisle of soldiers.

He was, indeed, a figure worthy of note. His appearance was in sharp contrast with the men he strode arrogantly between. His dress was colorful and quite barbaric in this stark setting. A blood-red cloak was slung across his shoulders, fastened at his throat with an elaborate brooch of gold. Beneath it was visible a tunic of bright green richly embroidered in gold thread. A heavy belt at his waist supported a silver-fitted scabbard and a long sword whose wide hilt was set with glinting jewels.

The garb was a complement to the striking nature of the man himself. Tall and wide of body, he was well muscled with no signs of extra weight. He carried himself with the unconscious easy grace of a warrior in full fighting trim. His hair was dark and very coarse, rolling back from his forehead in thick waves. His features were handsome but broad and crudely chiseled. The dark eyes were set deeply behind heavy brows and took in the preparations at the ship with sharp interest.

He strode down purposefully to the ship and stopped by its gangway. A uniformed man directing the work there moved to meet him. Several black bands encircling the soldier's lower sleeve were all that announced his rank to the rest.

"We sail in a few moments, High-King Bres," he announced to the brightly dressed arrival. "The tide is nearly at its peak."

"Very well Captain," said the other in a voice edged with irritation. "I'll go aboard."

He went up the gangway, but paused to look up toward the top of the Tower that loomed so far above him. There, a wider band of glass marked the structure's highest level. As distant as it was, he was certain that he could detect the dark shape of the one who watched. He was even certain he could feel the heat of that damned eye.

He was right. From far above, an eye was trained upon him. The crimson blaze of the single, fiery pupil was shuttered by its metal lid to a mere thread of ruby light. It stared down upon the ship below, and upon the tiny figure now climbing into it.

The face in which the eye was set was really no face at all. It was a rounded surface of burnished black, featureless except for the heavy lid that hung before the eye like a visor on a helmet. The head itself was no more than a barrel of metal, fixed to a short, thick neck that rose from massive, squared shoulders.

The whole being was enormous--over three times the height and girth of a normal man, all armored in the same smooth metal, fully jointed in the arms and legs, with hands like metal gauntIets. Standing there at the window, motionless, it might have been a lifeless object, like the metal ships below, save for the power of that eye.

And then a voice addressed it.

"Do you believe Bres can succeed in Eire alone, Commander Balor?" it asked, its tone hesitant.

There was no immediate response. Then, with an agonizing slowness and a faint, grating sound of metal on metal, the vast head began to move. It pivoted on the neck, bringing the crimson eye around from the window to those in the room.

The room was vast, befitting its main occupant. Three stories high, its outer wall was all glass, giving a view of the sea around the Tower to the distant horizon. Against the bright background of the dawn sky, the giant figure seemed all the more dark, all the more ominous to the three-men who stood before it.

The narrow beam from the single eye played over them. All wore the gray uniform. The many bands on the sleeves of each indicated exalted ranks. The eye shifted from one to another, finally fixing on the center man. From the figure a voice sounded, a deep and hollow and clanging sound, like a great gong echoing from the depths of some cavern of iron.

"It is necessary for him to succeed, Sital Salmhor. If he is unable to organize our occupying forces in Eire and crush this foolish uprising soon, it may spread to all the de Danann settlements."

Sital Salmhor stared up at the figure. As often before, he wondered if there was a living being there, behind that armored front. He steeled himself for another question.

"But shouldn't we send some support to him? Send some forces from the Tower? That would insure a victory."

"No!" the being thundered. "No forces from this Tower will be involved. Bres has the power to crush them if he acts quickly. And, remember, it is his own kingship over Eire that he must regain."

The offending officer held himself rigidly under the heat of the flaming eye. But the torture was short. The giant head turned slowly back toward the windows, the gaze of the eye shifting down toward the ship again.

It had put to sea by now and was gliding out past the sheltering peninsula. It moved along quite steadily, although no sail was up. But as it left the cove and the winds caught it, a field of brilliant white blossomed around its mast and it picked up speed quickly, soaring away with the grace of a great bird.

Until the ship faded into the haze of the southern horizon, the crimson eye stayed fixed upon its course.