"Why, he's up at Fort Clowdry--waiting--to--well, I guess I'll let Prescott tell it," finished Ensign Dave. For some reason Prescott blushed slightly, opened his mouth as though to speak, and then failed to do so. The reason for his confusion will appear later. By this time darkness had come on, and the cook, who was also the only cabin attendant, had switched on the electric lights in the snug cabin. The young officers, however, felt that they had so many matters to discuss that the deck would give them more room, so they adjourned. Some of the officers noted that Captain Foster frequently glanced down the river through the darkness, but none asked him his reasons. Finally, however, Sergeant Havens and ten men from F company marched on to the pier, followed by Corporal Shimple of H company and four men. In the wake of the two detachments walked Lieutenant Noll, who was soon shaking hands heartily with three of his brother officers of the United Services. "May I ask what you see coming, gentlemen?" inquired Captain Foster, suddenly, pointing down the river. "It looks like some pirate craft, sir," replied Hal, after peering hard through the darkness. "At least, that seems like a fair guess, for she's moving along without lights." "She's engaged in United States service of a somewhat stealthy nature," replied Captain Foster. "That's why the craft shows no lights. Mr. Overton, how do you like the idea that you're to command a gasoline boat yourself to-night, and one that is reputed to be exceedingly fast?" Hal Overton felt a sudden glow of exultation as the situation dawned on his mind. "I wired, last night, for a fast gasoline boat to be sent here to aid us," continued Captain Foster. "This coming craft is the answer to my prayer, and the nearest collector of customs informs me that she's the swiftest thing he could charter for the government in these waters." "Then, sir, if the Mexicans try to put their motor boat across the river to-night there'll be some real doings!" promised Lieutenant Overton. "Real doings," indeed! The border excitement was about to break loose in deadly earnest, but that was more than any of them knew at that time. CHAPTER XVIII AN ACT OF PIRACY Moving slowly, with the graceful ease of a monster swan, the motor boat, a craft under sixty feet in length, moved into the pier to shoreward of the tug. "Motor boat 'Restless'?" hailed Captain Foster. "Yes, sir," came quietly from the youthful-looking sailor at the wheel. Just then he quitted his post. "Captain Halstead?" "Yes, sir; here, at your orders." Skipper Tom Halstead made the best military salute that he knew how, while the handy boy of all things aboard the boat, Hank Butts, made the bow-hawser fast and hurried along the pier to secure the stern hawser. "A party of five United States officers coming aboard, Captain Halstead," continued Captain Foster.