"Against the wall!" the shadow hissed.

Rick dutifully moved back against the wall. The shadow was standing about six feet away.

Overhead, Scotty was climbing through the window now. Rick watched carefully as his pal lowered himself to full length, and swung _to the left_.

Instantly Rick divined Scotty's tactics. If the two boys were apart, the gun couldn't cover both of them at the same moment, and there would be an instant while the stranger jumped when only a single gun would be on them. And the shadow had already shown that he wasn't the smartest man in the world. Rick slipped to the right a step or two while the shadow was distracted by Scotty's jump. Scotty fell to his knees, and in getting up he managed to put a few more feet between himself and Rick.

"Watch 'em!" The stranger's voice floated down. Rick glanced up and saw the stranger with one leg over the sill. He tensed.

Scotty said, "Listen, you mug ..."

The shadow's head turned toward Scotty, and Rick left the ground in a wild spring. He struck the shadow, hand clawing for the gun. He found a wrist, and twisted, falling backward as he did so. The shadow, the entire weight of his own body on his wrist from the throw, screamed!

The gun landed on the ground. Rick let go and scrambled for it, but Scotty was there before him.

In the instant of the struggle the stranger had hesitated on the window sill, hand grabbing for the pistol he had tucked in his belt. He pulled it free and aimed at the struggling figures below, but in the gloom there was no way to distinguish friend from foe. And in that heartbeat, Scotty picked up the shadow's gun and fired one snap shot.

The stranger's gun dropped to the ground and he fell backward into the room.

Scotty thrust the pistol into the shadow's stomach. "Face the wall," he ordered. "Put your hands against it. Now support your weight on your hands."

The shadow did as ordered. Rick took the man's legs and pulled them backward so that the shadow's whole weight was against his hands, his outstretched body forming the hypotenuse of a right triangle. The only way he could move to regain his balance was to lower himself to the ground and then get up.

Rick picked up the stranger's fallen pistol and hefted it. "Better see about the one upstairs," he advised. "I'll watch this one."

"I fired at his hand, but I was high," Scotty told him. "He got it in the shoulder. He won't get far."

Zircon and Briotti charged around the corner of the hotel in pajamas and slippers, followed by other guests and members of the hotel staff.

"We had a little trouble," Rick explained briefly.

The scientists took in the situation at a glance.

"As I said," Tony Briotti muttered. "Adventure-p.r.o.ne. And lucky! How do you beat a combination like that?"

CHAPTER V

The Warning

Steve Ames walked into the hotel dining room accompanied by a young Navy lieutenant. He spotted the boys immediately and waved.

Rick breathed a sigh of relief. "There he is."

"We can turn this whole business over to him and then get out of here,"

Scotty returned.

The events of the night before had culminated in two phone calls, one by the hotel manager to the police, the other by Rick to Steve Ames.

However, the duty officer at the UDT base had replied that Ames was not available. Rick had then asked for intelligence, and his query had gotten fast results. Steve Ames didn't show up, but Navy Sh.o.r.e Patrol officers did. The SP's had conferred with the local police, and the affair had ended with the shadow and the stranger, whom Scotty had potted in the shoulder, being carried off by both groups. First, however, the senior Sh.o.r.e Patrol officer had listened to their story, then instructed the boys, "Wait for Steve Ames. Talk to no one else. The police won't ask any questions."

After conferring, the Spindrift group decided to go ahead with their plans. The scientists were anxious to transfer their activities to Clipper Cay, not only to get on with their vacation, but to get the boys away from the mysterious danger that dogged their footsteps in Charlotte Amalie.

The scientists had departed at dawn in the _Water Witch_, after extracting a promise from Rick and Scotty that they would not stir from the hotel until Steve Ames contacted them, and that they would then fly at once to Clipper Cay.

The wait had been a long one. It was now nearly noon, and the boys, hungry because their breakfast had been at daybreak, were ordering lunch.

Steve Ames sat down and motioned the lieutenant to a seat. "Jimmy, this is Rick Brant and Don Scott. Boys, Lieutenant Kelly. Have you ordered lunch?"

"We were just looking over the menu," Rick replied.

"Fine. We'll join you."

The four consulted menus, then ordered. Steve turned to Kelly. "Jimmy, being the athletic type, you've probably never heard of the Spindrift Scientific Foundation."

The lieutenant, a heavily tanned young man with crisp black hair, shook his head. "Sorry. I never have."

"Well, it's a reputable, highly competent and conservative group of some of the best scientific brains in the country. But somehow, these two got attached to it. They're not very conservative, although they're competent--especially at getting into trouble."

Kelly gave the boys a comradely grin. "If he talks that way, he must like you."

The boys grinned back. The lieutenant was likable.

"All right. Last I saw of you two, Rick was lying across the legs of the guy who had been tailing me. The next thing I heard, two men we've been keeping an eye on were in the hoosegow, one with a slug in his shoulder.

And I also heard some wild tales of jumping out of windows. Now fill in the details."

Rick started from the moment they first noticed that a shadow had picked them up. He told the story in careful and accurate detail, knowing that Steve's trained mind might find significance in things that meant nothing to him. Now and then Scotty elaborated on a point.

When Rick concluded the recital, Steve cupped his chin in one hand and stared at them thoughtfully.

Kelly complimented them. "Sounds as if you took care of things like real professionals, both in the water and in the hotel. And I must say, I wish my people would learn to give reports like that."

The boys thanked him, and Scotty added, "I don't suppose you can tell us anything about what you do?"

"Sure I can. I'm not one of Steve's hush-hush crew. I'm a simple Navy lieutenant."

Rick chuckled. "In other words, you can't tell us."

Steve said, "He's executive officer of the UDT group here. And he's group intelligence officer. I might also add that he's brighter than he looks."

"Then what do you make of this business?" Scotty inquired.

"I'm not that bright," Kelly replied. "Seriously, this one has me stumped. First of all, it's easy to understand why a shadow picked you up. After all, it must have been obvious that you knocked Steve's tail off. So they simply picked you up instead, hoping that you'd lead them back to Steve, or that you might be important in some way they couldn't understand."

"It's nice to have someone do my thinking for me," Steve said. "Carry on, Lieutenant."

"Aye, aye, Sir. The tail stuck with you. When your party split in two, he decided to stay with you instead of Zircon and Briotti. There could be two reasons: First, you were the ones who contacted Steve on the street. Second, you stayed at the waterfront while the others went off in a taxi. I like the second reason better because of what happened later. How about you, Steve?"