In spite of the medicine which she had taken, Grace was far too nervous and excited to fall asleep. She realized the daring nature of the game she had been called upon to play, and for a moment her spirits sank and she felt a sense of fear. Thoughts of Richard, however, soon restored her courage. She would face any danger to serve him. How different from what she had imagined, was this, her first night of married life! Instead of lying in Richard's arms, on board the steamer bound for America, here she was, a patient in a sanatorium in Brussels. The thing seemed unreal—impossible.

After a while, the noises of the house ceased one by one. As midnight struck, all was dark and silent. Only the faint sound of the wind among the trees in the park came to her ears. She wondered whether it was necessary for her to pretend to walk in her sleep this night—in order that the doctor might feel that her case was a real one. She rose softly, undecided, and going to the window, looked out.

The room in which she then was, occupied a position at the rear of the building, and in one of its two wings. From the center of the main building she observed a covered passageway, or bridge, extending out for perhaps a hundred feet and terminating in a sort of square tower. In one of the rooms in the tower, on a level with herself, she saw lights, and the figure of a man moving about.

The place attracted her attention. She wondered what its use could be. Then an inspiration struck her. The covered bridge ran from the main hall not thirty feet from her own door. She determined to cross it, pretending to be walking in her sleep, and find out what she could regarding the brick tower. When the time came, she knew that all the information she could possess about the house and its occupants would be necessary to the success of her plans.

She threw about her a dressing-gown, and quietly opened her door. The maid was nowhere to be seen, but doubtless she would shortly return. The chair upon which she had been sitting, at the point where the side and main halls met, stood directly beneath the electric light. No doubt, Grace thought, she had been called away for a few moments by one of the other patients on the floor.

Now was her chance. She stepped noiselessly down the cross hall, her eyes wide open and hands clenched at her sides. At the junction of the two halls she turned to the right, toward a door which, she judged, gave entrance to the covered way. She found this unlocked, opened it, entered the passageway and closed the door behind her. Then she began to walk slowly along the bridge.

It was a narrow structure, not exceeding five feet in width, with top and sides of corrugated metal, and a floor of wooden planks. At the far end of it she perceived a glass door, behind which shone a brilliant light.

She approached the door cautiously, keeping up all the while the pretense of walking in her sleep. This was not easy—she did not know just how persons who were somnambulists acted, but she had read descriptions of such cases, and had once seen a play in which one of the characters was a sleep walker. She tried to give her eyes a vacant, unseeing expression, and fearlessly approached the door.

It stood slightly ajar, and through the glass panels she saw at once that the room was Dr. Hartmann's laboratory. She arrived at this conclusion from the various medical appliances which stood about the room, the uses of which she did not know. Her inspection of the room, however, was but momentary, for two figures, brightly illuminated by an overhanging cluster of electric lights, at once attracted her attention. One of these was Dr. Hartmann. He sat at a large, flat-topped desk, his profile toward the door, examining with great care a mass of papers which lay on the desk before him. His forehead was wrinkled with thought, and an expression of anger dominated his face.

At the other side of the desk sat a tall spare man, with a military-looking carriage, and a fierce blond mustache, which he was gnawing uneasily. The two figures sat silent for several moments, no word passing between them, while Grace watched intently. Presently she heard the doctor speak. "It took you two years, it seems, to find out that Monsieur de Grissac uses snuff."