It was Christmas Eve, and, as usual, George Mason was the last to leave the office. He walked over to a massive safe, spun the dials, swung the heavy door open. Making sure the door would not close behind him, he stepped inside.

A square of white cardboard was taped just above the topmost row of strong-boxes. On the card a few words were written. George Mason stared at those words, remembering...Exactly one year ago he had entered this selfsame vault. And then, behind his back, slowly, noiselessly the ponderous door swung shut. He as trapped--entombed in the sudden and terrifying dark.

He hurled himself at the unyielding door, his hoarse cry sounding like an explosion. Through s mind flashed all the stories he had heard of men found suffocated in time-vaults. No time clock controlled this mechanism; the safe would remain locked until it was opened from the outside. Tomorrow morning.

Then the realization hit him. No one would come tomorrow--tomorrow was Christmas.

Once more he flung himself at the door, outing wildly, until he sank on his knees exhausted. Silence came, high-pitched, singing silence that seemed deafening. More than 36 hours would pass before anyone came--36 hours in a steel box three feet wide, eight feet long, seven feet high. Would the oxygen last?

Perspiring and breathing heavily, he felt his way around the floor. Then, in the far righthand corner, just above the floor, he found a small, circular opening. Quickly he thrust his finger into it and felt, faint but unmistakable, a cool current of air. The tension release was so sudden that he burst into tears. But at last he sat up. Surely he would not have to stay trapped for the full 36 hours. Somebody would miss him.

The maid who cleaned his apartment was just a servant; he had always treated her as such.

He had been invited to spend Christmas Eve with his brother's family, but children got on his nerves, and expected presents.

A friend had asked him to go to a home for elderly people on Christmas Day and play the piano-George Mason was a good musician. But he had made some excuse or other; he had intended to sit at home with a good cigar, listening to some new recordings he was giving himself.

George Mason dug his nails into the palms of his hands until the pain balanced the misery in his mind. Nobody would come and let him out. Nobody, nobody... Miserably the whole of Christmas Day went by, and the succeeding night.

On the morning after Christmas the head clerk came into the office at the usual time, opened the safe, then went on into his private office.

No one saw George Mason stagger out into the corridor, run to the water cooler, and drink great gulps of water. No one paid any attention to him as he left and took a taxi home. There he shaved, changed his wrinkled clothes, ate breakfast and returned to his office, where his employees greeted him casually.

That day he met several acquaintances and talked to his own brother. Grimly, inexorably the truth closed in on George Mason. He had vanished from human society during the great festival of brotherhood; no one had missed him at all. Reluctantly, George Mason began to think about the true meaning of Christmas. Was it possible that he had been blind all these years with selfishness, indifference, pride?

Wasn't giving, after all, the essence of Christmas because it marked to the time God gave His own Son to the world?

All through the year that followed, with little hesitant deeds of kindness, with small, unnoticed acts of unselfishness, George Mason tried to prepare himself...

Slowly he backed out of the safe, closed it. He touched its grim steel face lightly, almost affectionately, and left the office.

There he goes now in his black overcoat and hat, the same George Mason as a year ago. or is it? He walks a few blocks, then flags a taxi, anxious not to be late. His nephews are expecting him to help them trim the tree.

Afterwards, he is taking his brother and his sister- in-law to a Christmas play. Why is he so happy? Why does this jostling against others, laden as he is with bundles, exhilarate and delight him? Perhaps the card has something to do with it, the card he taped inside his office safe last New Year's Day. On the card is written, in George Mason's own hand: To love people, to be indispensable somewhere. That is the purpose of life. That is the secret of happiness.