LIKE A THIEF IN THE NIGHT.

The wind was dropping, and against the scurrying clouds, behind which shone a pale and sickly moon, they could see outlined a pyramid of canvas—the schooner!

“Don’t talk more than you have to,” said Nat, who had secured his firearm and brought oars for Joe and Nate. “If they come ashore, just follow them without exposing yourselves to view. There’s a chance that they may, after all, be honest fishermen, and we don’t want to attack the wrong men.”

“That chance is a pretty long one, I’m after thinking,” said Nate under his breath.

“We’ll see how they come to anchor,” he said presently. “If they let go their mudhook with a rush and a rattle, it may be that they are all right. But if they sneak in and let it go easy so as not to alarm anybody, why, then, it’ll look as if we’ve had ’em sized up right.”

The watchers crawled out and made their way through the spiky grass along one arm of the cove. They gained a point where it was possible even in the darkness to see the tall spars of the schooner and the black bulk of her canvas as, noiselessly as a phantom craft, she glided into the cove. Suddenly her “way” was checked and she came to a stop with all her canvas still standing.

“They’ve let go the anchor with all the sails set,” murmured Nate, “and they dropped that mudhook like a cat stalking mice. I reckon they’re honest fishermen—not. That’s a regular smuggler’s trick, that is, all right.”

“Why don’t they lower the sails?” was Joe’s not unnatural question.

“’Cos they don’t want the rattling of the blocks and the cordage to be heard,” rejoined Nate. “Seein’ no lights up above, I suppose they’ve figured that we are all asleep and dreaming. But we ain’t, not by a jugful,” he chuckled.

Then came the sound of oars as they creaked in the rowlocks of a small boat. Joe’s heart beat wildly with excitement, and even Nat felt a thrill, as there no longer remained any doubt that hostile men were about to land on the island. When Hank had told Joe the day before of old Israel’s plans of vengeance, he had not taken them very seriously. Now, however, they faced the fact, and faced it to all intents and purposes unarmed.

“Lie down,” ordered Nat, as the sound of the oarsmen became more distinct; “we don’t want them to see us yet.”

They all threw themselves flat amidst the spiky dune-grass and waited for what was to come. Presently they saw a small boat grounded on the beach, and five men leaped out. They grouped themselves about one figure, which Nat instinctively felt must be that of old Israel himself.

At any rate, he appeared to be giving orders to the others. The group split up. Two of the men started in the direction of the shanty, while three, including the one suspected to be old Israel, set out to the southward.

“Now what in the name of time does that mean?” demanded Nate in an astonished voice.

“It means that our job is just twice as hard,” rejoined Nat. “I can’t make out myself exactly the object of it, but I reckon we shan’t be long in finding out.”

“We’d better follow them,” suggested Nate.

“Yes, we had better. Nate, you take the two men that went toward the hut. Joe and I will trail that group of three.”

“All right, Nat; and say, if you’re in trouble, just fire a shot from that shootin’ iron of yours and I’ll come on the jump.”

“All right, Nate, I won’t forget. We might need you badly in case of a mix-up.”

“You can sure count on me,” the sturdy waterman assured them.

Then they parted, Nate striking off toward the shanty, whither two of the strangers had preceded him, and Nat and Joe taking the trail after the trio, one of which they firmly believed was none other than old Israel himself.

Through the darkness they made the best speed they could after the old smuggler and his two sons, for they now knew by the sound of the voices that had been flung back to them on the wind that their surmise had been correct. It was old Harley himself and his rascally offspring who had landed on Goat Island under the cover of night.

At first their motive in so doing had been plain enough to Nat, or at least he had thought it was. Now, however, he was by no means so certain that the destruction or injury of the wireless was the sole object of their call. This striking off through the dark to the southerly point of the island was inexplicable to the boy, and as they made their way along, sometimes stumbling over rocks and clumps of beach-plum bushes, he confided his bewilderment to Joe.

“I wonder what all this means?” he said. “There’s nothing to the south, so far as I know, but some low cliffs and waste land.”

“I’ve no more idea than you have,” rejoined Joe, equally puzzled. “One thing is sure and certain, though, they are not out for a pleasant stroll.”

“No, they’ve got some definite object in view, and I’m inclined to believe that we don’t figure in it as prominently as we thought we did,” was Nat’s rejoinder.

They paced on in silence, always keeping the three figures in front of them in view, but creeping along as close to the ground as they could and taking advantage of every bit of cover that offered.

“Say, Nat,” exclaimed Joe after a while, “it’s my belief that they are making for those old ruins!”

“You mean the remains of that mission that the early missionaries from Spain built here?” asked Nat, referring to a jumbled pile of adobe ruins which were supposed to mark the site of one of the early religious houses of California.

“That’s what. See, they’re striking off to the right.”

“That is the direction, sure enough, but what would they want there?”

“We can only find out by following them. Hullo, what are they doing now?”

The group ahead had halted not far from the pile of debris and heaped-up stone and wood that marked the remains of the monks’ establishment.

One of them stooped low while the others shielded him from the wind. Then came a sputter of flame as a match was struck, and then the steady glow of a lamp or lantern. With this means of illumination kindled, the party that the boys were breathlessly trailing proceeded once more.

Suddenly Nat stopped short and seized Joe’s arm.

“The lamp, Joe, it’s gone!” he cried, pointing to the midst of the ruins where the lamp had been last seen.

Sure enough, the lantern had suddenly vanished, leaving the boys deeply mystified as to the cause of its sudden disappearance.

“They must have some hiding place among the ruins,” exclaimed Nat excitedly, “That is why old Israel was so mad about our being on the island! What shall we do?”

“Follow them,” said Joe determinedly. “We’ve started on this thing, let’s see it through.”

They struck out toward the ruins at a half run. In their excitement, prudence was temporarily thrown to the winds. Soon they were stumbling and barking their shins amidst the ruinous pile. In the dark it was almost impossible to see their way. All at once Nat, who was in the lead, gave a sharp exclamation:

“Get back, Joe! Back, as quick as your legs will let you!”