Never had Toby Tew “staged” at his Palace a better “presentation” than the one the chums were about to enact. With the Police Chief aiding, they had worked out a plan that must almost certainly bring their quarry to them.

Don, with excited face, raced through the designing section of the big hangar’s upper floor, at the end. Doc saw him; Toby saw him; so did others, under suspicion.

“All right, Chief!” he shouted over his shoulder, “sorry we haven’t room in the Dragonfly to take you along; but we’ll signal with a set of red, white, and blue flares when we find the treas—after we’re through.” He pretended to correct his supposed slip.

Old Ti-O-Ga barred his way to the door.

“You find?” he grunted.

“Think so!” Don admitted. “Tell you better after I’ve made sure!”

“Where you think you find?” The old Indian stood firm.

Don was secretly delighted: this gave him an opportunity.

“You see,” he explained, “after a photograph was made of your map, it was enlarged, and a tracing was made, of the larger size. That tracing was disguised with airplane parts, but it still looked like the hull of some kind of boat, a brig, or a brigantine. The ‘ghost’ was plotting the swamp out in narrow strips. The design enabled him to put lines across, looking like inch and foot divisions—but they were all sections of the swamp. You see, he flew to and fro, over the swamp, taking moving pictures. Then he kept a projector head here, in a locker, and when nobody was on this floor, at night, he’d develop his films, dry them in our dark room, and then project them by putting the projector head in front of our enlarging camera lamp. He was searching for any place that looked as though a ship had gone down. But—he was all wrong.”

“How was he ‘all wrong?’” demanded the control chief eagerly.

“He was looking for a sunken brigantine—or some sort of boat!”

“How was that so ‘wrong?’” the mail pilot, lurking in the background, wanted to know.

“We saw through the camouflaged design,” Don said. “We had a developed picture, what camera men in the movie colonies call a ‘shot’ of the swamp, from very high up—a wide-angle shot! It showed all the creeks and channels. We compared that with the blue-print we had—that the ‘ghost’ didn’t take away!” he spoke meaningly, “and we saw that the little mark probably indicating the treasure place, in the real map, that looked as if it was just a frame joint in the airplane sketch, and showed the treasure in the hold of the ‘brigantine’ at the stern, was really a mark at a point in one of the swamp channels!”

“You don’t say!” Scott bent forward.

“You see, the part of the map that looks like the deck of the brig—is—Crab Channel!”

“In the name of all-possessed!” cried Toby Tew, “tell us the rest—quick!”

“The wavy line is the other channel, almost parallel with Crab Channel,” Don was willing enough to speak, “and the line that looked like the stem of the ship was really the shore line between the channels while——”

“The bow part must have been the—” Doc Morgan was shaking with excitement, “—the little channel alongside of the boathouse.”

“Gosh-a-mighty!” Toby leaped up, “that cross in the tracing was right by the boathouse, then. In the name of all-possessed—to think I’ve been storing dories right over treasure—let’s——”

“Just a moment!” The Police Chief entered with Mr. McLeod. “Nobody goes out of here except Don and his Airlane Guard. The treasure is the Indian’s property if found. No one else gets a chance to rush ahead and secure it—if found! Stand aside, Ti-O-Ga!”

The Indian, realizing that he must obey, moved away. Don dashed out.

Anyone in the upper windows at the hangar side, watching, could have seen the Dragonfly take off almost before it had rising speed, and go roaring into the dark swamp air. They could have seen, and some did see, a landing flare go over near the sheet of water where the boathouse stood.

“Did you telephone—and get the answer we expected?” Don asked Garry as they tied up the Dragonfly to a part of the old wharf.

“I did, and Chick is about to unload what he found—in the boarding house room you mentioned!”

They took some cased objects, and a projector head, out of the cockpit, carried them into the old hovel, set them up by hooded flashlight rays, and then sat down in a corner to wait.

The water slapped and gurgled under the flooring. An hour passed. The wind that changes at dawn began to sigh and moan through the cracks of the old wall.

“Well—” Don stretched, wearily, “it’s almost dawn. Maybe our plan won’t work—listen! Here comes—somebody!”