There was no moon to reveal their movements as they approached the rear of the house.  The evening was warm, and one of the windows had been left open.  Noiselessly they crept up to it and looked within.  It opened into a large room used as a dining hall, where they could see all of the men clustered about one of the tables, at the head of which sat old Otto Hoff with Frederic at his side.  On the table before him was what appeared to be a rough map or blueprint.  Frederic and five of the other men, Fleck observed, now wore aviation costumes.

“Comrades,” old Otto was saying in German, “here is the course.  You will have no difficulty in following it.  Down the river straight till you see the lights of New York.  You each understand what you are then to do, yes?”

“Certainly,” three of the men, the pilots evidently, responded.

“Let us, to make sure,” old Otto insisted, “once more rehearse it.  Much there is at stake for the Fatherland.  You, Anton and Fritz, will blow up the transports and the warships that guard them.  Six great transports are lying there, ready to sail at daylight The troops went aboard to-night.  We waited until it was signalled that it was so.  You must not fail.  The biggest of those transports once belonged to Germany.  You must teach these boastful Americans their lesson.  That one boat you must destroy for certain.  Beside the transports to-night lie five vessels of war, two battleships, three cruisers.  Them you must destroy also, if there is time.  To each transport, two bombs, to each warship, two bombs—­twenty you carry.  If all goes well, two you will have left.  With these do what you will, a house, a church, it matters not—­anything to spread the terror of Germany in the hearts of these money-grabbing Americans.”

“It will be done,” said Anton solemnly.

“I have thrown bombs before.  You can trust me,” said Fritz.

“You, Hans and Albert,” old Otto went on, “will fly over the city at good height.  When you reach the end of the island you turn to the left, so, and come down close that your aim may not miss.  Here will be the Brooklyn Navy Yard,”—­he indicated a place on the map.  “If there is fog the bridges will locate it for you.  Smash the ship lying there, the shops, the dry docks; if it is possible blow up the munitions stored there.”

“I know the place well,” Hans replied.  “I worked there many months.  I can find my way in the dark.  It will be done.”

“And to you, Herr Captain,” said Otto, turning to Frederic and saluting, “to you, whom the War Office itself sent here to oversee this all-wonderful plan of mine which it has seen fit to approve, to you and your mate falls the greatest honor and glory.  You—­”