Presently some one began to whistle a popular air, but in such a way that the boys recognized the well-known whistle of Adrian.

"Do you hear that?" asked Billie. "Ad wants to know what we are doing."

"He'll have to want for the present," said Don, "but there go a couple of officers back to the train. Let's follow them."

The boys darted into the shadow of the coaches and crept back only a few steps behind what proved to be the captain in charge of the company and his second lieutenant.

"If I only had my automatic, I'd soon settle this whole matter,"

declared Billie.

"You wouldn't hurt anybody, would you?"

"I'd capture the officer and make him take us to Vera Cruz."

"Of course," from Donald. "Why didn't I think of it before? Let's do it."

"But we have no weapons."

"Then we must get some."

"How?"

"Keep your eyes open. There must be some way."

The officers kept on their way until they reached the first Pullman, where they stopped for a minute.

"Are the orders in here?" asked the captain.

"No; the conductor has them. He wouldn't stop the train without I gave them to him."

"Carramba! Why didn't you tell me so before? Go and take them from him and bring them here at once."

"Bueno, Capitan! Will you wait here?"

"Yes, I'll go inside. Hurry."

The lieutenant turned and hurried back. The boys only saved themselves from being detected by throwing themselves flat on the ground.

For a moment the captain remained looking after his companion and then turned and entered the car.

"We must have that order," said Donald.

"We must!" echoed Billie.

"Then we'll get it," they exclaimed as one.

So alike were the thoughts that pa.s.sed through their minds that they did not even feel obliged to speak the plan aloud.

"Which one of us will stop him?" asked Donald.

"You'd better. I'm heavier and I can handle him easier."

They walked back some ten feet, where Donald stopped, while Billie went about ten feet farther and drew off into the darkness.

A couple of minutes later they heard the lieutenant coming. He pa.s.sed 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, h.e.l.lo, 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 p.r.i.c.k 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."