The next day, having instructed his father and the foremen to look well to the various shops, and having seen that the work on the new aerial warship was progressing favorably, Tom left for a day's outing with his chum and the two girls. The picnic was held in a grove that surrounded a small lake, and after luncheon the four friends went for a ride in a launch Tom hired. They went to the upper end of the lake, in rather a pretty but lonesome locality. "Tom, you look tired," said Mary. "I'm sure you've been working too hard!" "Why, I'm not working any harder than usual," Tom insisted. "Yes, he is, too!" declared Ned, "and he's running more chances, too." "Chances?" repeated Mary. "Oh, that's all bosh!" laughed Tom. "Come on, let's go ashore and walk." "That suits me," spoke Ned. Helen and Mary assented, and soon the four young persons were strolling through the shady wood. After a bit the couples became separated, and Tom found himself walking beside Mary in a woodland path. The girl glanced at her companion's face, and ventured: "A penny for your thoughts, Tom." "They're worth more than that," he replied gallantly. "I was thinking of--you." "Oh, how nicely you say it!" she laughed. "But I know better! You're puzzling over some problem. Tell me, what did Ned mean when he hinted at danger? Is there any, Tom?" "None at all," he assured her. "It's just a sort of notion--" Mary made a sudden gesture of silence. "Hark!" she whispered to Tom, "I heard someone mention your name then. Listen!" CHAPTER XII A NIGHT ALARM Mary Nestor spoke with such earnestness, and her action in catching hold of Tom's arm to enjoin silence was so pronounced that, though he had at first regarded the matter in the light of a joke, he soon thought otherwise. He glanced from the girl's face to the dense underbrush on either side of the woodland path. "What is it, Mary?" he asked in a whisper. "I don't just know. I heard whispering, and thought it was the rustling of the leaves of the trees. Then someone spoke your name quite loudly. Didn't you hear it?" Tom shook his head in negation. "It may be Ned and his friend," he whispered, his lips close to Mary's ear. "I think not," was her answer. "Listen; there it is again." Distinctly then, Tom heard, from some opening in the screen of bushes, his own name spoken. "Did you hear it?" asked Mary, barely forming the words with her lips. But Tom could read their motion. "Yes," he nodded. Then, motioning to Mary to remain where she was, he stepped forward, taking care to tread only on grassy places where there were no little twigs or branches to break and betray his presence. He was working his way toward the sound of the unseen voice. There was a sudden movement in the bushes, just beyond the spot Tom was making for. He halted quickly and peered ahead. Mary, too, was looking on anxiously.