So Gruin came to know the worst fear the known holds for us: fear of madness. But that fear did not last long. It very speedily deepened into that last ultimate horror--of the _un_known--which can prey on a man's mind. Mad because he seemed to hear the weird clicking of heels beside him? _Seemed_ to hear? He went into the library one night when his grandfather sat at his desk, reading. It was late, and the house was very still. The old man's senses were excellent. He didn't become aware of Gruin's entrance for a moment, but then he glanced up quickly, with a slightly surprized expression. "Oh," he said, carelessly. "You're alone." "Of course. Why?" "It sounded for a moment as though there were two of you," the old man said. "A sort of clicking. It must have been your hard heels against the floor." Gruin managed to get out of there without letting his grandfather see the chaos in his brain. But he staggered like a drunken man after leaving the library. "Sounded as though there were two of you ... must have been your hard heels against the floor." God! Gruin didn't wear hard leather heels. Every shoe he owned had rubber on it. "A sort of clicking...." The clicking of Maria José's small red heels as they twinkled unseen beside him! Maria José, who had died in flame and ruin at the bottom of the cliff! He was _not_ mad, then. The sound he had thought to hear in madness, actually was there to be heard. And then Gruin knew that ultimate horror which comes with the unknown. For if the sound really was there, perceptible enough for others to hear it, the cause of the sound must be there too! A dead girl walking beside him! A thing from some unknown sphere! "_Walking when you walk, stopping when you stop_----" "I walk with death!" Gruin told himself, shuddering, with the icy sweat of horror on his forehead. Red heels clicking beside him, as small, unseen feet kept time with his. As Maria had kept time when they walked down the street together. With one difference. Maria, alive, had been unable to match his strides when he increased them to their full masculine length. Maria, dead, could do that. He caught himself crazily shortening and lengthening his step as he walked down the street--with people turning to look curiously after him. But no matter how he walked, the unseen little heels beside him clicked in even pace. Walking with death. Escorting a dead girl wherever he went. Sometimes Gruin talked with her, damning her, whispering curses, telling her to get back to the grave from which she had come. And more people began to turn to look after him as he walked the streets. His grandfather and his friends began asking him what was wrong, and he couldn't tell them. His grandfather sent him to a great psychiatrist, and Gruin couldn't tell him what was wrong, either. Confession as to what was wrong with him lay too dangerously close to a murder confession.