Terry yelped, lost balance, and recovering desperately, dived over her head. His departure rocked the float, so that Phil Stanton’s lanky figure poised on the diving board, lurched and fell awkwardly into the water.

Betty Mayo, hugging her damp knees on the middle of the float, shrieked her approval of this double exploit.

“Swell work, Dorothy!” she laughed as that young lady pulled herself aboard. “You’ll catch it in a minute though!”

Dorothy stood up. Her scarlet bathing cap flamed against the ash blue sky and her wet suit clung to her slender form like a sheath of black lacquer.

“Maybe!” Then, in quite a different tone: “Goodness, Betty, he’s missing!”

Betty sprang to her feet. “You’re crazy – ” she retorted as she caught sight of Phil and Terry knifing their way back to the float. “Why’d you try to scare me? Those boys are all right.”

But Dorothy was staring skyward.

“Not the boys! I mean the plane, Betty. Over there beyond the club house. His engine’s missing. Bet you an ice cream cone he’ll have to land!”

“No, you won’t,” Betty flashed back. “I don’t know a thing about airplanes, and I’ll take your word for it. Ooh, Dorothy – do you think he’ll hit the roof?”

“Oh, he’s all right – ”

“Yes, he’s over the roof now – but look!” Betty’s voice rose to a shriek. “He’s aiming the plane straight for us – it’ll hit this float – ”

The last word was no more than a gurgle. Betty had dived overside.

Dorothy did not trouble to turn her head. With her bare feet firmly planted on the timbers, her straight body balanced easily to the float’s gentle rocking, she gazed interestedly at the big amphibian sweeping down toward her.

On came the plane, losing altitude with every split second, and sailed over her head a bare thirty feet above the water. Then as she faced about to watch it land, the tail of her eye caught sight of Terry hauling himself over the edge of the float.

“Get you for that last one!” he cried, and scrambled to his feet. “‘Who laughs last,’ you know!”

“I know – ” mocked Dorothy, evading his grasp and running up the springboard. She dived and her body entered the water with scarcely a sound.

As she rose she turned lazily on her back.

“Come and get me!” she tantalized. Then as she saw him start in pursuit, she rolled over and headed out toward the seaplane which now floated two or three hundred yards away toward the mouth of the inlet and Long Island Sound.

Terry knew the speed developed by her flagrantly perfect crawl, and did not attempt to follow her. He chuckled as he watched the bob of scarlet and the flash of a brown arm that was all he could see of Dorothy.

“Hey, where’s Dorothy?” called Betty as she and Phil clambered on to the raft.

“Halfway to Boston, I guess. Race you to the beach for the cones!”

All three cut the rumpled surface of the water with a single splash.

Dorothy’s interest in the airplane that had just landed was twofold. Since qualifying for her private pilot’s license earlier in the summer, she had met most of the owners of planes living in or near New Canaan. To the best of her knowledge the Loening Amphibian which her father had given her for rounding up the Martinelli gang was the only one of that model privately owned in that part of Connecticut. That the plane lying just ahead on the water was a duplicate of her own meant that the owner was not a local person.

Dorothy was a keen aviatrix and proud of her airbus. She wanted to compare notes with the owner of this amphibian. She was also curious to learn where the plane came from; and why every day for the past few weeks it had appeared over the Club at about this same time of an afternoon. At five-thirty sharp the crowd of young people on the beach would see it, a speck in the north, coming from over the ridge country back of the Sound. Flying at an altitude of not more than five hundred feet, it would swing over the beach club and cross the Sound, to disappear in the ether toward the dim line of the Long Island shore.

Terry jokingly termed it the Mystery Plane. He told Dorothy that its owner made these daily flights in order to show her how a plane should be managed in the air. She usually returned his good-natured teasing with interest, but each time she saw the amphibian, her curiosity increased.

As she swam nearer it was plain that this airship was actually the same stock model as her own. With the retractible landing wheels drawn up, the spoon-shaped hull of the biplane, with its two open cockpits aft of the inverted engine, floated easily on the water. The aviator, she saw, was busily engaged in going over his engine.

Dorothy stopped swimming when she was a few yards from the amphibian.

“Hello, there!” she called, treading water. “Need any help?”

The man looked up from his work, evidently perceiving her for the first time. Dorothy was surprised to see that the face below the soft helmet and goggles was bearded to the eyes.

“No, thank you,” he answered and went on tinkering with the motor. The words, although courteous enough, were spoken in a tone that showed plainly that he wished to end the conversation then and there.

Dorothy was persistent and not easily discouraged.

“Located the trouble?” she asked.

“Not yet,” replied the man without lifting his head.

“Looks like loose manifold, or gas connection, to me.”

There was no reply to this helpful suggestion.

She began swimming toward the plane again.

“Mind if I come aboard?” she called.

The bearded aviator straightened his back and faced her again, his right hand grasping a monkey-wrench.

“No. I do not wish it,” he flared. “Why for do you bother me? Keep off, I tell you.”

For the first time, the girl in the water noticed his strong foreign accent.

“Aren’t you polite!” she mocked. “I don’t suppose you’ll mind if I come alongside and rest a moment?”

“You stay where you are, young woman.” As the man’s anger grew, his accent became stronger. “I haf no time to bodder wid you. Go away – and stop away!”

“But I just want – ”

“I don’t care what you want. Come alongside, and I’ll use this wrench on you!”

“Oh, no you won’t!”

Terry Walters slipped round the engine and tripped up the aviator. Before that irate person knew what was happening he found himself flat on his back with a hundred and sixty pounds of young American kneeling on his chest, menacing him with his own monkey-wrench.

“That’s not a nice way to talk to a lady!” Terry remarked dispassionately eyeing his victim. “Ask her pardon like a good little boy. Do it quickly, my friend, or I’ll plant this wrench in the middle of that bush you call a face!”

“I didn’t mean nossing,” the man grunted.

“Try again!” Terry whacked his captive’s shin with the wrench. “Also try to cut the double negatives. Our English teacher says they’re bad form and – ”

Terry’s banter stopped with a yelp of pain as the man’s head jerked upward and his teeth snapped on the hand which held the wrench.

Dorothy, who had swum to within a few feet of the amphibian, saw Terry thrown to one side. Like cats, the boy and the man seemed to land on their feet – but now it was the strange aviator who held the monkey-wrench.

“Look out, Terry!” shrieked the girl as she saw the man’s arm swing upward.

The small deck forward of the lower wing section was far too narrow to permit dodging. Terry did the only thing possible under the circumstances to save himself. Three seasons on the football team of the New Canaan High had made that young man a quick thinker. He dove below the swinging blow and tackled the aviator just above his knees. It was a well aimed tackle and the two went hurtling overside to disappear with a splash.

Terry’s blond head was the first to appear. Then as the aviator’s came popping up, facing the other way, young Walters seized him by the shoulders and sent him under once more.

“Let the man alone, Terry!” commanded Dorothy. “Can’t you see he’s swallowed half the Sound?”

“But he’d have brained me with that wrench, Dot – ”

“I’ll ‘Dot’ you if you take liberties with my first name!” Miss Dixon shook her fist above her head, “Anyway, it’s my fault. I butted in. That man and his plane are none of our business.”

They were swimming back toward the float now and a glance over her shoulder told Dorothy that their late antagonist was pulling himself aboard the amphibian.

Terry saw him too, and waved a hand. But the foreigner, occupied in wringing water out of his clothes, disregarded them.

“I’ve had enough of the water for one day,” declared Dorothy between strokes. “How’s the wrist? You might have been badly hurt, Terry.”

Terry motioned toward the float. “But I wasn’t, old thing,” he chuckled. “Come over to the raft a moment, before we go ashore. I’ve got something I want to show you.”

“Make it snappy, then,” she rejoined. “You and I have got to be at Silvermine by seven-thirty, you know. Curtain up at eight-thirty – and you remember what Mr. Watkins said about any of the cast being late?”

Terry swung himself up on the decking and gave a hand to Dorothy.

“I’m only a chorus man,” he grinned. “We’ll both get to the Sillies in time. Look at this – ”

He opened his hand and held it out, palm upward.

“I’m not interested in seaweed!” Dorothy’s tone was full of disgust.

“Seaweed, nothing! That’s a piece of your friend’s beard!”

“You don’t mean to tell me you pulled it out?”

“Not out, dearie – off. That wasn’t his own hair that lad was wearing.”

“A false beard?”

“What else?”

Dorothy pursed her lips. “Well, that amphibian and its pilot are two of the most mysterious things I’ve ever run into.”

“I wonder what he is up to, Dot – I mean, Dorothy?”

“I wonder, too. By the way, how did you happen out there – and just at the right minute? I thought I saw you start a race for the beach with Betty and Phil?”

Terry nodded his wet head and laughed. “That was only a bluff to make you think I wasn’t coming after you. As I saw you were having an argument with him, and I didn’t like the way he was acting, I swam around the tail of his plane and got aboard on the farther deck – and – well, you know the rest. Why did you want to go aboard?”

“Curiosity, pure and simple. Have you any idea why he flies over the Club nearly every afternoon, and always at the same time?”

“No – have you?”

“Not the dimmest. But now that I know friend pilot wears false whiskers, I’m certainly intrigued.”

“Come again,” frowned Terry. “I didn’t get that last one. Did you say intrigued?”

“Cut the clowning. This is serious, Terry. That fellow is up to some mischief, or he wouldn’t disguise himself.”

Behind them the amphibian’s engine sputtered, then roared.

“I’ve got an idea,” said Terry as the two watched the plane taxi out toward the takeoff. “Why don’t you get your bus and follow that bird some afternoon?”

“I’d already decided to do it tomorrow. Want to come?”

“You bet! How do you expect to work it?”

“Look here, if we’re going to make that show on time, we’d better go right now. We’ll make our plans later. Come along.”

Their bodies cut the water with hardly a splash as they raced for the beach. Out in the inlet the amphibian rose gracefully into the air and headed into the mist which was creeping up Long Island Sound.

Chapter II
THE THREE RED LAMPS

In the wooded valley of the Silvermine, some three miles from the village of New Canaan, lies the famous artists’ colony which bears the name of that rippling little river. In the midst of this interesting community, the artists have built their Guild House, where exhibitions of paintings and sculpture are held. And here it is that once a year they give that delightful entertainment known as the Silvermine Sillies.

The casts of the Sillies invariably comprise the pick of local talent from the two communities. Dorothy had starred in the musical show given by the New Canaan High School the previous winter. She had a lovely voice and a natural talent for acting. She loved amateur theatricals. But that she should have been assigned a part in the Sillies while yet in High School was a compliment beyond her expectations. She had worked hard at rehearsals and under an assumed calm was wildly excited on this, the opening night of the show.

She left Terry on the beach, after cautioning that young man again not to be late, and ran up the shingle to the Dixons’ cabana, which, together with its gaily painted counterparts, flanked the long club house at the top of the beach.

A surprisingly few minutes later, Dorothy reappeared, her bathing suit having been discarded for an attractive linen sports frock, and jumped into her car.

The distance between Tokeneke on Long Island Sound and New Canaan back in the hills of the Ridge Country is slightly under eight miles. Luckily, on her drive home, Dorothy encountered no traffic policemen. Not withstanding summer traffic and the narrow, winding roads, she pulled into the Dixon garage on the ridge a mile beyond the village, a bare ten minutes later.

Another change of costume and she ran downstairs to the dining room. Her father and a friend were about to sit down at the table.

“Sorry to be late, Daddy,” she apologized, slipping into her chair. “Good evening, Mr. Holloway.”

“Good evening, Miss Dorothy,” returned the gentleman with a smile. “You seem a bit blown.”

“Some rush!” she sighed, “but I made it!”

“Youth,” remarked her father, “is nothing if not inconsistent. We dine early, so that Dorothy can get to the Sillies at some unearthly hour, and – ”

His daughter interrupted.

“Please, Daddy. I had an awfully exciting experience this afternoon. I’d have been home in plenty of time, otherwise.”

“At the Beach Club?”

“Yes, Daddy.”

“Well, suppose you tell us the story, as penance.” He turned to his guest. “How about it, Holloway? This should interest you, one of the club’s most prominent swimming fans!”

Mr. Holloway nodded genially. He was older than Mr. Dixon, between fifty and sixty, tall and rather thin. He had the brow and jaw of a fighter, and his iron-grey side-whiskers gave him a rather formidable appearance. But Dorothy liked him, for his eyes, behind his horn-rimmed spectacles, beamed with friendliness.

“The Beach Club, eh?” He leaned back in his chair. “Yes, I take a dip most afternoons. Wonderful bracer after mornings in the city in this hot weather. You ought to get down there more often.”

“Well, there’s a pool at the Country Club, and I’d rather play golf,” argued his host. “I haven’t been to the Beach Club this summer, but Dorothy tells me that the cabana you’ve built is quite a palace – much larger and more ‘spiffy,’ I think was the word, than those we ordinary members rent!”

“I like to be comfortable and have some privacy when I entertain my friends down there,” Mr. Holloway admitted. “But I’m interested in hearing Dorothy’s story. I was there this afternoon, but I didn’t notice anything unusual.”

“Did you see the airplane that landed in the cove?”

“Why, no. What time was that?”

“A little after five-fifteen.”

“I had already left for home. I’m rarely at the club after five o’clock. I like a bright sun when I’m in the water. What about the plane?”

While Dorothy told of her experience with the bearded pilot, the two gentlemen continued their meal in silence.

“A nasty customer – that!” snapped her father when she had concluded. “But then, my dear, you shouldn’t allow your keenness for aviation to over-excite your curiosity. Let it be a lesson to you not to interfere with other people’s private business.”

“You say that he wore a false beard?” interjected Mr. Holloway. “Now I wonder why the man wants to disguise himself? And why he was so standoffish about his plane?”

“He’s probably in training for some test or endurance flight and wants to keep his identity secret for the time being,” suggested Mr. Dixon. “There’s often a lot of hush-hush stuff about such things – that is, until the stunt comes off – and then the secretive ones become the world’s worst publicity hounds!”

Dorothy remarked the change that came to their guest’s face: the eyes narrowed, the mouth grew harder; something of his levity disappeared.

“Perhaps,” he said slowly. “But whatever his reason for wishing privacy, we can’t have club members insulted by strange aviators in our own cove. I shall take it up at the board of governors’ meeting tomorrow. In future we will see to it that no more airplanes land on club waters. Do you think you would recognize the man without his beard, Dorothy?”

“I don’t think so – but Terry, who was nearer to him, swears he could spot him anywhere.”

“If he should do so, ask him to report the matter to me, and I’ll see that the man at least offers apology.”

“Thank you, Mr. Holloway.” Dorothy was pleased at this interest. “I’ll tell him.”

“You three had better leave well enough alone,” her father declared bluntly. “The plane is probably being flown over a set course which happens to take it over the club. That aviator seems to be a surly customer. My advice is to forget it…”

Dorothy pushed her chair back from the table.

“You’ll excuse me, won’t you?” she smiled. “I’ve got to run, now.” She went to her father and kissed him. “Please don’t be late, Daddy. I come on the first time right after the curtain rises – it will spoil my evening if you two aren’t there!”

Mr. Holloway’s kindly eyes twinkled behind his glasses.

“Nice of you to include me. I wouldn’t miss the first number for anything. I’ll see that we’re both there in time.”

“Don’t worry, sweetheart.” Her father patted her hand. “We’ve got a small matter of business to go over and then we’ll be right along. Success to you, dearest.”

“’Bye!”

A fine rain was falling when Dorothy stepped into her car. As yet it was more a heavy mist than a downpour. But with the wind in the east she realized that this part of the country was in for several days of wet weather. She drove carefully, for the winding wooded roads were slippery. Upon arriving at the Guild House, she changed at once into costume.

The Silvermine Sillies, like Mr. Ziegfield’s more elaborate Follies, is invariably a revue, consisting of eighteen or twenty separate acts. As Dorothy stood in the wings, waiting for her cue, shortly after the first curtain rose, she was addressed by the stage manager:

“Have you seen Terry?”

“Not since this afternoon. Why?”

“He’s not here.”

Dorothy was fighting back the stage fright that always assailed her while waiting to “go on,” but which always disappeared as soon as she made her entrance. She turned her mind to what the manager was saying with an effort.

“You mean he hasn’t shown up?” she asked a bit vacantly.

“Your perception is remarkable,” returned the harassed stage official with pardonable sarcasm. “No, Terry isn’t here. Do you know whether he had any intention of putting in an appearance at this show tonight when you last saw him?”

Dorothy was wide awake now. “Of course he had!”

“He didn’t mention some more important date, perhaps?”

“Of course not. Terry wouldn’t do such a thing!”

“Well, he goes on in less than two minutes. Who in blazes am I to get to double for him? Deliver me from amateurs! There’s your cue, Miss Dixon – better take it!”

“Hey, you, Bill!” she heard him call to a stage hand, as she made her entrance. “Duck into the men’s dressing room and bring me Terry Walters’ overalls and wig. Here’s where I do his stuff without a makeup!”

Terry failed to show up during the first part of the program, so during the intermission, Dorothy slipped out front and sought the delinquent’s father and mother in the audience.

“Why, my dear, I’m quite as surprised as you are,” gurgled Mrs. Walters. “Isn’t this rain disgusting? You looked perfectly lovely Dorothy – and you did splendidly, splendidly, my dear. I thought I’d die when your rope of pearls broke and you went hunting for them – a perfect scream, my dear – the funniest thing in the show!”

“Those were Betty Mayo’s pearls,” said Dorothy. “I wasn’t in that act. You say Terry left the house in plenty of time, and he expected to drive straight down here?”

Mrs. Walters had said nothing of the kind, but Dorothy had known the lady for years, and had long ago devised a method of securing information from her.

“He didn’t even wait for dessert, my dear. He probably went to the movies or remembered some other date. Boys are like that!”

“Terry isn’t.” His father spoke up. “He must have been going to pick someone up and give them a lift down here – then blew a shoe or something. Still, I don’t like it. I hope the boy hasn’t met with an accident.”

“Oh, don’t say that, Reggie! You make me feel positively faint. I know he has gone to the pictures.” Mrs. Walters was nervously emphatic. “Don’t be so silly, dear – I know he has.”

“You know nothing of the kind,” declared her husband.

“But, Reggie dear – ”

Dorothy hurriedly excused herself and went back stage.

But by the time the final curtain was rung down, no Terry had appeared. Dorothy was really worried. Betty was giving a party to a number of the cast at her house in White Oak Shade, but despite protests, Dorothy made her regrets and went to look for her father.

“I think I’ll beat it for home, Dad,” she announced, buttonholing him near the door.

“I’ll be along in a few minutes, darling. I certainly am more than extra proud of you tonight. I never realized what an actress you are. But you look troubled – anything the matter?”

“I’m worried about Terry. I know he wouldn’t deliberately put us all in this hole. He’s not that kind.”

“Probably had a break-down,” consoled her father. “Excuse me, dear, I want to speak to the Joneses over there.”

Dorothy drove a six-cylinder coupe whose body had seen better days, though she claimed for its engine that the world had not seen its equal. With her windiper working furiously, she came cautiously along Valley Road, her big headlamps staring whitely ahead. The rain was pelting down now, and since she must have a window open, and that window was on the weather side, one arm and part of the shoulder of her thin slicker were soon black and shining.

“Something he couldn’t help – that’s what made Terry let us down,” said her subconscious mind, and she wondered how any of the cast could have expressed contrary opinions. She was glad she had refused Betty’s invitation. She liked Terry and was deeply concerned about him. He wasn’t the sort to default unless something unforeseen and unusual occurred. Mrs. Walters said he had been full of the show at dinner and had spoken about getting to the Guild House early. Something had come up, that was certain. And that something, after he had started for Silvermine in his car. The more she thought about it, the more mysterious it seemed. She would phone the Walters again as soon as she reached home. Maybe he would be back by that time.

The car skidded round the turn into the Ridge Road that ran past the Dixon place. A mile farther on, Dorothy decided it would be well for her to keep her mind on the road ahead. A few minutes before, a lumbering truck had almost driven her into the ditch, and now, with a mile to go, she saw ahead of her three red lights. She slowed her engine until she came within a dozen yards of them.

They were red lamps, placed in a line across the road, and if they meant anything, it was that the road was under repair and closed. Yet she had passed the truck going at full speed just beyond the corner. From its lights, she was sure it had come along this stretch of road.

She peered through the open window and saw on her left a dilapidated stone fence, the top of which was hidden under a blanket of wild honeysuckle. She saw by her headlights a gap where once she knew a five-barred gate had blocked the way to the open field. All this she took in at a glance, for Dorothy knew exactly where she was. Then she turned again to her scrutiny of the road and the three red lamps.

“Well!” said Dorothy to herself. She switched out all the lights of the car, and taking something from her pocket, she opened the door quietly and stepped into the rain. She stood there for a while, listening.

There was no sound except the swish and patter of the storm. Keeping to the centre of the road she advanced slowly toward the red lights, picked up the middle one and examined it. The lantern was old – the red had been painted on the glass. The second lantern was newer, but of entirely different pattern. Here also, the glass pane had been covered by some red, transparent paint. And this was the case with the third lamp.

Dorothy threw the middle light into the ditch and found satisfaction in hearing the crash of glass. Then she came back to her car, got inside, slammed the door and put her foot down on the starter. The motor whined but the engine did not move. The car was hot and never before had it failed. Again she tried, but without success.

“This looks suspicious,” she muttered to herself.

She sprang out into the rain again and walked to the back to examine her gasoline tank. There was no need, for the indicator said, “Empty.”

“I’ll say suspicious!” she muttered again, angrily, as she stared down at the cause of her plight.

She had filled up just before dinner, but notwithstanding that fact, here was a trustworthy indicator pointing grimly to “E”; and when she tapped the tank, it gave forth a hollow sound in confirmation.

Dorothy sniffed: the air reeked with fumes. Flashing her pocket light on the ground she saw a metal cap and picked it up. Then she understood what had happened. The roadway, under her light, gleamed with opalescent streaks. Someone had taken out the cap and emptied her tank while she was examining the red lamps!

She refastened the cap, which was airproof, waterproof, and foolproof, and which could only have been turned by the aid of a spanner – she had heard no chink of metal against metal. She did not carry reserve fuel, but home was not more than a mile down the road, round the turn. And she knew there was a path from the gap in the stone wall, across the field and through a belt of woods that would halve the distance.

She sent her flashlight in the direction of the open gateway. One of the posts was broken and the rotting structure leaned drunkenly against a lilac bush. In the shadow behind the bush, she was certain that a dark form moved.

Dorothy lingered no longer, but switching off her light, she turned on her heel and raced up the road.