But they did not know that at the moment when they had stepped from David’s cabin into the passage, a man had slipped like a shadow into another room; a man, who, just outside David’s open door, had listened to the conversation between the two friends. The listener stood deep in thought. “In the suitcase, eh?” he whispered. “Well, there’s no hurry.” * * * * * But that night Red woke suddenly. David, a flashlight in his hand, was shaking him. He was very pale. “Wake up, Red!” he said. “The plans are gone!” CHAPTER XIV ON THE OBSERVER’S PLATFORM Red lunged up, awake in an instant. “What’s that?” he demanded. “The plans are gone; you were right.” Red, swearing softly and fervently, commenced to throw on his clothes. “No use cussing,” said David. “We’ve got to think what to do. I just left the wheel, and what you said kind of worried me, so I thought I’d hide ’em. I opened the case, and they were gone.” “Did you look around?” asked Red. “Of course; but they are not in the cabin.” “What’s the time?” “Three.” Trouble came scrambling up, curled around in Red’s lap, and commenced to purr. Automatically Red scratched the small ear. “Gone!” he repeated. “Well, they have got to be somewhere. Just one thing to do, Dave. Go to Mr. Hammond the minute he’s up, and tell him the whole thing. It’s a dirty scandal, of course, but those plans must be found. Let’s go down.” “Easy does it,” warned David. “Don’t want to wake anybody.” Silently, thoroughly, they searched every inch of David’s room. The plans were not there. They could not sleep, so they sat in the salon and smoked. There Mr. Hammond found them when, as usual, he came out at dawn. Briefly they told him what had happened. “By George,” he said, “that’s a rotten shame! Who on earth would do it? Whom do you suspect?” “Well, sir,” said Red grimly, “my brother always says, ‘Don’t ever lose time suspectin’ anybody. Look for a motive’.” “There’s a good deal in that, but I confess I don’t see any motives just now. Wonder if there is any coffee left over. This has upset me.” “I’ll make some, sir, if you can keep the cook from stabbin’ me later,” said Red, and he went into the spotless galley. While Red made coffee, David explained something of the nature of the device minutely described in the stolen plans, what he had hoped it would mean to dirigible navigation, and his high hopes of winning the Goodlow School prize with it. When Red returned with the steaming percolator Mr. Hammond tested the brew with evident satisfaction. “Perfect,” he said. “Now I can think. We have been talking this invention over, Red. Why, it is a great thing! Just what we have been groping for. If it is a success, it is immensely valuable. The papers must be found.” “They must,” said Red, “for it will work. I know it!”