There was a double line of the footprints—one set coming toward the door, one set going away from it. Ken stared at them for a long moment.
Suddenly he realized that he was clearly visible, through the glass, to anyone who might be outside the house. Quickly he dropped the curtain into place and with a swift gesture he fastened the safety chain above the lock on the door.
Then he ran to the back door and fastened the safety chain there.
The events of the past few moments were perfectly clear in his mind. He sat on the edge of the kitchen table and ran over them again, trying to explain them to himself as he went along.
He had stepped out of his bedroom and had almost immediately felt the draft of cold air. Probably the front door was just then being opened. The faint click he had heard
