The detective had seen a bustle on the deck of the yacht which he believed signified that a boat was being lowered. But if it was, they were dropping it on the other side, and he could not make out enough of their movements to be sure what was going on.

“If it isn’t a boat, then I don’t know what they’re after,� he murmured, under his breath. “Hello! What’s that?�

Far out, some little distance from the yacht, his glasses had enabled him to distinguish a phosphorescent flash, repeated again and again on the dark surface of the bay.

Nick Carter had seen phosphorescent gleams of this kind too many times not to be able to interpret the meaning of any particular kind or number.

A single one, or even many, might have been caused by the jumping of fish. That would flash up the bright glow so often seen in mid-ocean at night.

But regular gleams, such as Nick saw now, and which developed into shining patches one by one, could have been caused only by the regular dipping of oars. The space between the patches represented the width of a rowboat.

“They are rowing two pairs,� he murmured. “And the boat is rather heavy, too. What are they after?�

As they came nearer, he could see that there were five black patches in the boat, and it did not take him long to resolve these patches into men, two were rowing and one was steering. The other two sat still.

“This looks like a fight, if we want to save Drago,� muttered Nick, rather louder than his musings had been so far.

“What?� asked Corrigan.