She stumbled along at his side over the rough floor of the temple, saying nothing more, panting with eagerness to return to her incomprehensible "tree." How much of that eagerness was assumed Smith still could not be quite sure. When they reached the door he halted her for a moment, scanning the sky for danger. Apparently the ships had finished with this quarter of the city, for he could see two or three of them half a mile away, hovering low over Illar's northern section. He could risk it without much peril. He led the girl cautiously out into the sun-hot court.

She could not have known by sight that they neared the well, but when they were within twenty paces of it she flung up her blurred head suddenly and tugged at his hand. It was she who led him that last stretch which parted the two from the well. In the sun the shadow tracery of the grille's symbolic pattern lay vividly outlined on the ground. The girl gave a little gasp of delight. She dropped his hand and ran forward three short steps, and plunged into the very center of that shadowy pattern on the ground. And what happened then was too incredible to believe.

The pattern ran over her like a garment, curving to the curve of her body in the way all shadows do. But as she stood there striped and laced with the darkness of it, there came a queer shifting in the lines of black tracery, a subtle, inexplicable movement to one side. And with that motion she vanished. It was exactly as if that shifting had moved her out of one world into another. Stupidly Smith stared at the spot from which she had disappeared.

Then several things happened almost simultaneously. The zoom of a plane broke suddenly into the quiet, a black shadow dipped low over the rooftops, and Smith, too late,