"We'll have to get in some way," returned Jack, "or else admit that we are wrong."

"I won't admit I'm wrong," declared Frank grimly. "I feel positive the man is Davis."

"So do I," replied Jack; "else I wouldn't be so keen about getting into that house. We'll go back and skirmish around a bit, anyhow."

They retraced their steps slowly, and pa.s.sing the house where the man had entered, took careful note of it.

It was a two-story building. Steps led to a porch, not high above the street, but still high enough to make the single window in front beyond reach from the street below. A narrow pa.s.sage was between it and the house on the left. It was built flush against the house on the right.

At the corner the lads again turned and retraced their steps. "I'm going to try the door," said Jack. "You slink back in that dark alleyway until you hear from me."

Frank signified that he understood, and pa.s.sing the house, did as Jack had instructed, the latter mounting the steps quietly and swiftly.

The lad laid a hand on the k.n.o.b and turned it. Then he pushed on the door, but it held fast.

"Locked," he said, plainly disappointed.

There was no window in the little vestibule and the single front window was beyond reach from the porch. Neither was there a transom that could be forced.

"No means of getting in here," Jack told himself.

He descended the steps and joined Frank in the alleyway.

"Well?" Frank greeted him.

Jack shook his head.

"Can't get in that way," he said.

"Well," said Frank, "I have been doing a little exploring while you were up there and I have found a way."

"How?" asked Jack, a little surprised.

For answer, Frank motioned to a little aperture in the side of the house, close to the ground.

"Window into the bas.e.m.e.nt," he explained. "It's open."

Jack wasted no time. He dropped to his hands and knees and, pushing the window open, shoved his feet through. Then he wriggled his body through the opening and dropped.

It was not a hard fall and he picked himself up unhurt. He called softly to Frank and the latter was beside him a moment later. Walking softly, Jack led the way up a little flight of stairs to a door which opened easily. He stepped inside.

Frank followed and Jack closed the door. It was perfectly dark.

But suddenly the darkness was lighted up. The astonished lads gazed into the muzzles of a pair of automatics and a well-known voice cried:

"Hands up!"

CHAPTER XXIV.

ANOTHER UNPLEASANT SURPRISE.

To say that the lads were astonished is putting it mildly. There they were, so they believed, sneaking upon an unsuspecting victim and now they found themselves absolutely in that victim's power, for it took but the first glance to a.s.sure them that the face that gazed so evilly and sardonically into theirs was the face of Davis.

Now Davis grinned at them.

"I was expecting you, gentlemen," he said with biting sarcasm. "I did not wish to seem discourteous, which is the reason I welcome you in person. But, also, knowing your kind, I surmised that you would not announce yourselves at the front door, as would most British gentlemen; therefore I receive you here. I a.s.sure you you are most welcome."

All this time he kept each lad covered with an ugly-looking automatic.

As neither Frank nor Jack replied, Davis continued.

"I would just like to add that if you desire to get ahead of me it will be necessary to arise very early in the morning. What kind of a spy do you think I am, anyway, not to know when I am being followed? I a.s.sure you, gentlemen, you have misjudged me. I was not born yesterday."

Still neither lad replied.

"And now," Davis went on, "I must ask you to be so kind as to precede me to the parlor, where I shall entertain you more comfortably."

He emphasized this statement with a slight gesture with one of his revolvers and there was naught for the lads to do but obey.

Davis followed them closely, still covering them with his two revolvers.

In the parlor he motioned them to seats and took a chair across the room.

"Now," he said, "I would be pleased to have you tell me how you escaped from our enemies, the British."

"Well, I can see no harm in enlightening you," said Jack. "I would have supposed that, being so brilliant, you had guessed it by this time. We are British officers and not German."

"Would it surprise you," queried Davis, "if I should tell you I had surmised as much? And our good friend, Commander Bernstorff"--and here Davis laughed--"how is he?"

"Well," replied Jack calmly. "And now I wonder if you would explain a few things to me?"

"You are at liberty to ask," smiled Davis.

"Then, how did you get here--why did you venture here--and what of your little private expedition?"

"Those," said Davis, "are what I should call considerable questions.

However, I can see no harm in answering them, particularly as you will never be able to repeat what you hear now. I came here in our submarine the U-16, which, by the way, I have rechristened _The Vulture_--a suitable name, don't you think?--and I came here because I had business here. Now, as to your other question. Our little privateering expedition is progressing famously. We have already sunk one British ship and secured a quant.i.ty of booty, which may have something to do with my presence in Ostend."

"I see," said Jack.

"And," continued Davis boastingly, "I came in right under the noses of the Germans. My submarine lies in the harbor at this moment. I came ash.o.r.e in the guise of a German officer. I was not questioned, nor were you, I take it?"

His last words formed a question, and Frank answered.

"No, we were not questioned," he said.