At four o'clock Isabel was awakened by suspicious sounds at the key-hole of the front door. She reached out for her pistol, but withdrew her hand as she heard the careless laugh of her brother-in-law. A few moments later the two explorers, after an instant's hesitation at the head of the stair-which they had climbed like cats-walked past her door with a brisk swaggering preternaturally steady gait that invoked the memory of former occupants of the mansion. Then Gwynne's door opened and shut as if by sleight of hand. Stone's was at the end of the hall. Isabel inferred that he went through it, and a sound between a hiss and a smothered roar shot down the hall as he would seem to pick up the door and bang it into place.
Mr. Hofer had mentioned his luncheon hour as half-past one. Isabel had G
