"Well, where is the houseboat?"
It was a question neither of them could answer. They looked out on the river, but the mist hung over everything like a pall.
"Dick, I am afraid something serious has happened," came from Tom, ominously. "Those screams weren't uttered for nothing."
"Let us make a closer examination of the shore," answered the oldest Rover, and they did so. They found several hoofprints of horses, but that was all.
"I can't see any signs of a struggle," said Tom.
"Nor I. And yet, if those rascals ran off with the houseboat and with the girls on board, how would they square matters with Captain Starr?"
"And with Captain Carson? The tug is gone, too."
"Yes, but the tug went away when we did, and wasn't to come back until to-morrow morning. Captain Carson said he would have to coal up, over to one of the coal docks."
"Then some other tug must have towed the houseboat away."
"Either that or they are letting the Dora drift with the current."