As the cyclists, far behind, came down a long winding hill on which they had managed to catch occasional glimpses of their quarry, Dean, with a muttered exclamation, put on a sudden burst of speed.  At a rise in the road he had seen the Hoffs’ car swing sharply to the left.  Furiously he negotiated the rest of the hill, arriving at the base just in time to see them boarding a little ferry the other side of the railroad tracks.  While he and Jane were still five hundred yards away the ferryboat, with a warning toot, slipped slowly out into the Hudson.

In blank despair they turned to face each other.  The situation seemed hopeless.  They dared not shout or try to detain the boat.  That surely would betray to the Hoffs that they were being followed.  Despondently Dean clambered off the motorcycle and crossed to read a placard on the ferryhouse.

“There’s not another boat for half an hour,” he said when he returned.  “They have gained that much on us.”

“Perhaps we can pick up their trail on the other side of the river,” suggested Jane.  “There are not nearly so many cars passing as there would be in the city.”

“We can only try,” said Dean gloomily.

“At least we know where to pick up their trail the next time.”

“Damn them,” cried Dean, “I believe they suspect that they may be followed and time their arrival here so as to be the last aboard the ferryboat.  That shuts off pursuit effectually.  They make this trip every week.  I wouldn’t be surprised if they have not fixed it with the ferry people to pull out as soon as they arrive.  A two-dollar bill might do the trick.  I’d give five thousand right now if we were on the other side of the river.  It’s the first time—­the only time I’ve ever failed the Chief.”

“Never mind,” said Jane consolingly, “why can’t we be waiting for them at the other side next week when they come up here?  They’re not apt to suspect motorcyclists they meet up here with having followed them.”

“Perhaps next week will be too late.”

“I wonder where they are headed for,” said the girl, looking across at the rapidly receding boat.  “Why, look!  What are those buildings over there?”

“That’s West Point,” Dean exclaimed, noting for the first time where they were.

“West Point!” she echoed in amazement.

What mission could the Hoffs have that would take them to the United States Government military school was the question that perplexed them both.  Could it be that the web of treachery and destruction the Kaiser’s busy agents were weaving had its deadly strands fastened even here—­at West Point?

CHAPTER X

CARTER’S DISCOVERY

“It’s the young man I’m after,” said Chief Fleck.  “We have the goods on old Hoff, but we have nothing incriminating against Frederic yet.  The very fact that he holds aloof from his uncle’s activities makes me think he is engaged in more important work.  He’s just the type the Germans would select as a director.”