"We shall have to search the vessel!" affirmed the orderly. "You will please remain aboard for a short time."

Quickly ascending the ladder the man summoned another soldier from the sh.o.r.e. Together the two made a hasty examination of the boat.

Unable to discover any trace of the missing prisoner they shook their heads as if greatly puzzled. Now and again they glanced at the boys, exchanging at the same time comments in German.

"Come with us," finally said the first visitor.

Obediently the lads followed ash.o.r.e. They were conducted to the office building, where they were shown into the presence of General Gruenwold at once. In a few words the orderly stated the case.

"This looks serious, boys," commented the General. "Can you not explain the whereabouts of Mackinder? He is a prisoner, you know!"

"We know nothing of the man!" declared Ned, earnestly. "We don't like him and surely would not think of a.s.sisting him to escape!"

"If you please, sir," began the orderly, "it is the opinion of my comrade and myself that the boys have done away with Mackinder!"

"What!" almost shouted Gruenwold, rising from his chair.

"Yes, sir," continued the man. "There was found in the boat much blood. A hammer in their tool kit was also blood-stained. We think they possibly made away with him and might have dropped his body into the harbor very quietly without being seen from sh.o.r.e!"

"This is serious, indeed!" gasped Gruenwold. "We shall investigate this in the morning. Meanwhile, search the vessel again. The boys will be put in the guardhouse until tomorrow."

Protests on the part of the lads were unavailing. Gruenwold was determined in his decision. Ned's explanation of the presence of the blood in the vessel was listened to, but without influencing the general.

Directly the lads found themselves in a room used for the accommodation of such prisoners as might need confinement for a time. The island boasted no regular prison, but a house not far from the water had been utilized for the purpose. A guard paced a beat in the vicinity.

Disappointed and angry at the turn of affairs the lads made but a poor supper of the food that was brought to them. Presently they composed themselves to sleep on the floor.

A tapping at the window attracted their attention.

CHAPTER XIV

HELPED BY AN ENEMY

"What's that?" inquired Ned, startled at the unexpected sound.

"Loose board, I guess," replied Jimmie, rather disgruntled at the turn affairs had taken. "The wind's ripping everything loose!"

Again the tapping was repeated in an insistent manner.

"I'm going to see what's going on here!" declared Ned, rising from his position. "Some one is trying to communicate with us!"

"Some bloomin' Dutchman's tryin' to ask us whether we want sausage with our pancakes for breakfast!" growled Jimmie. "Let 'em alone!"

Disregarding this statement the older lad proceeded toward the window, where fitful gusts of sleet beat. Outside the darkness covered everything. Only an occasional point of light indicated a sentry hut.

"Who's there?" demanded Ned in a low tone.

"Sh-h-h!" came a hiss from the darkness. "Open the window!"

Ned fumbled a moment at the fastening. Presently he found the catch sliding the sash back in its channel. An exclamation escaped him as he did so. The face of the visitor was none other than that of their missing acquaintance, Mackinder. Ned was astounded.

"Thought you were dead!" he cried in amazement.

"Hush!" cautioned the other. "Not so loud. Now, if you lads want to get out of here this is your time. Everybody's busy or asleep!"

"How do you know we want to get out of here?" demanded Jimmie in a low tone as he approached the opening.

"Don't you suppose I have eyes? I saw what you were up to!"

"Oh, you did, eh? Then what do you want us to do?"

"If you want to get away from this place according to your plan, now is the time to take action," replied Mackinder in a whisper. "If you prefer to wait until tomorrow and stand trial for an offense of which you are innocent I cannot offer any objection of course."

"Ned, I think we'd better make our getaway while the going's good!"

"Second the motion!" declared Harry, who had softly approached the window. "Let's make a noise like a drum!"

"I'm with you!" stated Frank, raising a foot to the window sill.

"Easy there!" cautioned Jimmie. "Mind your step!"

Frank was through the window in an instant. He landed on the earth with Mackinder's a.s.sistance without noise. Quickly the others followed. Ned took the precaution to slide the window shut.

Cautiously the little group of six made their way in the direction of the wharf where the submarines were moored. Mackinder took the lead as if familiar with the ground. Once he paused, extending a warning hand to Jimmie, who was directly behind him. The lad performed a similar service for those in the rear. A sentry was approaching.

Mackinder sank upon the ground. Although the night was too dark for the lads to see this action they were close enough to be aware of the movement. Instantly all followed suit.

In a moment they breathed more freely. The sentry had pa.s.sed within a few paces of their position. Evidently his feeling of security in the isolation of the island had made him somewhat negligent of his duties. He proceeded against the storm with head bent low.

Again Mackinder rose to his feet. Cautiously he crept forward.

On tiptoe the party gained the shelter of the warehouse.

"Gee!" declared Jimmie as the edge of the wharf was gained, "I clean forgot my kit! What shall we do?"

"Hush!" warned Ned. "Don't even dare think of your kit!"

"I should say not!" put in Harry. "Think of your head instead!"

"And the mines at the harbor entrance," added Frank.

"All right!" submissively agreed Jimmie. "I'll keep quiet!"

The wind had risen to such an extent that walking on the narrow planking was not only uncertain but extremely dangerous. Mackinder solved the problem by dropping to all fours. The boys followed suit.