Dick was glad of the chance to get the assignment. So far he had not had an opportunity to prove his ability as a diver to Captain Austin and he was anxious to make good. What a fine thing if he could be instrumental in reclaiming for the United States Government the long lost plans and scientific formulas! It had been hinted that among other things, the stolen plans included the formula for manufacture of the deadly gas that U. S. chemists had discovered just before the close of the war. "I'll certainly do my level best," soliloquized Dick as he floundered along on the sea bottom in the direction of the U-boat. Very soon he came in sight of it. The sun, shining strong on the surface of the sea, lit up the whole area of clear water so that he was able to see quite a distance in front of him. Through the green haze of the sea he discerned suddenly the figure of another diver. He was dragging after him a long rectangular box of some kind. Undoubtedly it was Weddigen! But what was he doing and what was the chest that he dragged with so much effort? "The plans!" gasped Dick. In an instant it was clearly revealed to him. Weddigen had succeeded in getting into the submarine and had salvaged the stolen plans! What was Weddigen doing now? Dick stopped short in his tracks to watch the maneuvers of the other diver. CHAPTER XI THE SPY! Peering intently through the water Dick watched every move of Weddigen. The latter had knelt on the sandy bottom and was tinkering with the steel chest. His back was turned to the Brighton youth and he, to all intents, had no knowledge of the proximity of the latter. And then Dick made an astounding discovery. Weddigen had unfastened the extra air hose from his belt, turned on the air and was digging a hole in the sand some ten or fifteen yards away from the submarine. A cloud of sediment was stirred up by the air which for the time served the purpose of hiding the diver at his work. Dick's first impulse was to move forward hastily and make known his presence, thinking perhaps Weddigen was having trouble lugging the chest and needed assistance. But then, it occurred to him, why would Carl be digging a hole with the air line when he had already salvaged the precious box? Why had he not gripped it with a steel cable and sent it aloft to the _Nemo_? "By jove! I know what he's doing," exclaimed Dick to himself. "He's trying to lose those plans under the floor of the sea rather than give them back to the government!" The youth saw red on the instant. A traitor to America! An enemy of the United States Government who, rather than return the plans that he had found, was trying to cover them up where he might return later and dig for them at his leisure.