A couple of minutes later they heard the lieutenant coming. He passed Billie without seeing him. Then Donald advanced and met him as by chance. "Who comes there?" asked the lieutenant in a sharp tone, drawing his revolver. "Why, hello, lieutenant," said Donald as he came close to him. "What's happened?" The lieutenant eyed him suspiciously. "Where did you come from?" he asked. "From the rear sleeper. I woke up and found myself all alone." "Humph!" grunted the lieutenant. "You must have been overlooked. Come with me." He started to replace his revolver in its holster when a slight noise behind him caused him to turn his head. As he did so, Billie's fist caught him under the chin and he fell in a heap without making a sound. "Good work!" muttered Donald as he picked up the revolver which the lieutenant had let fall. "Now to business." CHAPTER IX. DONALD'S STRATEGY. Lifting the unconscious man in their arms, they bore him into the darkness away from the train, where he was soon deprived of his coat, hat, and weapons. Then he was gagged and securely tied with his own sabretasche. Donald, being nearest the lieutenant's size, donned his uniform, buckled on his sword, and with the order in his hand hastily entered the car, closely followed by Billie, with the ready revolver in his hand. The captain had thrown aside his hat and was smoking a cigarette in one of the easy seats as the boys entered. He gave them only a hasty glance as he blew a cloud of smoke into the air, and the next minute he was covered by Billie's weapon. "Up with your hands!" was the stern order. The captain hesitated, but a sharp prick from Donald's sword sent the hands into the air. In another minute the captain was disarmed. "Now," said Donald sternly, "we'll see what all this trouble is about." He opened the telegram he held in his hand and read: "American Admiral has given an ultimatum. Hold train and passengers until further orders. Maas." "Who is Maas?" asked Donald sternly. The captain shrugged his shoulders, but said nothing. "You'll answer in just one minute, or you'll never have a chance to answer another question," said Donald, as he stood with drawn sword, while Billie covered the captain with his revolver. "Would you murder an unarmed man?" asked the captain. "I wouldn't consider it murder. Answer." The look in Donald's eyes was not to be mistaken. "Gen. Maas is in command of Vera Cruz," the captain said. "Good. I think I see it all. If it is decided not to accede to the ultimatum, it is proposed to hold the train load as hostages." The captain smiled. "Now listen!" and Donald spoke very slowly so that every word might find lodgment. "You have one chance for your life. Can you guess what it is?" The captain shook his head. "To do just exactly as I bid. Just one little attempt to do differently, and you are a dead man." The captain scowled, but made no reply.