Then she called Jim Preston's home and learned that he had left fifteen minutes before and should be almost down to Linder's.

"We'll go down to the landing and wait for Jim," said Mr. Linder as he lighted a lantern he had brought from the kitchen.

"Everything will come out all right," Mrs. Linder a.s.sured Helen.

The farmer led the way down to the landing. The wind was freshening rapidly and Helen saw Mr. Linder anxiously watching the white caps which were pounding against the sandy beach.

Down the beach their picnic campfire was a red glow and Helen could see Miss Hughes and the girls huddled around it. The boys who had not accompanied Ned Burns were walking up and down along the sh.o.r.e.

She turned and looked up the lake. Two lights, one red and one green, the markers of the _Liberty_, were coming down the lake.

"Jim Preston will be here in another minute," said Mr. Linder, "and with the searchlight he's got on the _Liberty_ it won't take us long to find Doctor Stevens' daughter."

Helen nodded miserably as the _Liberty_ slowed down and swung its nose toward the Linder pier. There was the grinding of the reverse gear as Jim Preston checked the speed of his boat and left it drift against the pier.

"Don't shut it off, Jim," cried the farmer. "Doc Stevens' daughter is adrift in the lake in one of my rowboats. We've got to go out and look for her."

They climbed into the boat and Jim Preston backed the _Liberty_ away from the pier.

"How did it happen?" he asked Helen. She told him briefly and he shook his head, as though to say, "too bad, it's getting to be a nasty night on the lake."

The boatman opened the throttle, the motor roared its response and the _Liberty_ leaped ahead and down the lake. They ran parallel to the sh.o.r.e until they were opposite the picnic ground. There Jim Preston slowed down, got the direction of the wind, and turned the nose of the _Liberty_ toward the open and now wind-tossed lake. He snapped on the switch and a crackling, blue beam of light cut a path ahead of the boat.

"Keep the searchlight moving," he directed the farmer, who stood up in the _Liberty_, his hands on the handles of the big, nickel lamp.

The boatman held the _Liberty_ at about one third speed and they moved almost directly across the lake while Mr. Linder kept the searchlight swinging in an arc to cover the largest possible area.

A third of the way across they sighted a boat far to their right and Jim Preston swung the nose of the _Liberty_ around sharply and opened the throttle. They sliced through the white caps at a pace that drenched them with the flying spray but they were too intent on reaching the distant boat to stop and put up the spray boards.

Helen's keen eyes were the first to identify the boat.

"It's the boys," she cried. "They're beckoning us on."

Jim Preston checked the _Liberty_ carefully and nosed alongside the tossing rowboat.

"No sign of Margaret," admitted Ned Burns, "and the lake's getting too rough for us to stay out much longer. We've had half a dozen waves break over us now."

"Better get in with us," advised Preston.

"Hand me the oars," said Mr. Linder, "and we'll let the rowboat drift.

I'll pick it up in the morning."

The boys tossed their oars into the _Liberty_ and scrambled up into the motorboat.

Jim Preston threw in the clutch and the _Liberty_ leaped ahead to resume its search for Margaret. Helen's lips were dry and fevered despite the steady showers of spray and her heart hammered madly. Lake Dubar had always had a nasty reputation for ugliness in a fresh, sharp wind but Helen had never before realized its true danger and what a lost and helpless feeling one could have on it at night, especially when a friend was missing.

There was no conversation as the _Liberty_ continued across the choppy expanse of the lake. The searchlight picked up the far sh.o.r.e of the lake with the waves hammering against the rocks which lined that particular section. It was a grim, unnerving picture and Helen saw Jim Preston's jaw harden as he swung the _Liberty_ around the cross back to Linder's side of the lake.

Back and forth the searchlight swung in its steady, never tiring arc, but it revealed only the danger of Lake Dubar at night. There was no sign of Margaret.

They reached the sh.o.r.e from which they had started and turned around for a third trip across the lake. This time they slapped through the waves at twenty-five miles an hour and every eye was trained to watch for some sign of the missing boat and girl.

Helen caught a flash of white just as the searchlight reached the end of its arc.

"Wait!" she cried. "I saw something far to the right."

Preston slapped the wheel of the _Liberty_ over and the speedboat roared away in the direction Helen pointed, its questing searchlight combing the waves.

"There it is again," Helen cried and pointed straight ahead where they could discern some object half hidden by the waves.

"That's one of my boats," muttered old Mr. Linder as they drew nearer, "but it doesn't look like there was anyone in it."

"Don't, don't say that!" cried Helen. "There must be someone there.

Margaret must be in it!"

In her heart she knew Mr. Linder was right. The boat was rolling in the choppy waves and there was no one visible.

"It's half full of water," exclaimed Ned Burns as they drew nearer and Jim Preston throttled down the _Liberty_ and eased in the clutch.

Helen pushed them aside and stared at the rowboat, fully revealed in the glaring rays of the searchlight. Tragedy was dancing on the waters of Lake Dubar that night, threatening to write an indelible chapter on the hearts of Helen and her cla.s.smates for there was no sign of Margaret in the boat.

"Maybe she shoved the boat out into the lake and hid in the woods," said Ned Burns.

"She wouldn't do that," protested Helen.

They edged nearer the rowboat, Preston handling the _Liberty_ with care lest the waves created by the boat's powerful propeller capsize the smaller boat.

"There's something or someone in the back end," cried Ned Burns, who was three or four inches taller than anyone else in the boat.

Helen stood on tip-toe.

"It's Margaret," she cried. "Something's wrong. It looks like she's asleep."

But sleep in a water-logged rowboat in the middle of Lake Dubar was out of the question and Helen realized instantly that something unusual had happened to Margaret, something which would explain the whole joke which had turned out to be such a ghastly nightmare.

Jim Preston eased the _Liberty_ alongside the rowboat and Mr. Linder reached down and picked Margaret up. There was a dark bruise over her left eye and her clothes were soaked.

The boatman found an old blanket in one of the lockers and they wrapped Margaret in it and pillowed her head in Helen's lap.

Margaret's eyes were closed tightly but she was breathing slowly and her pulse was irregular.

"Hurry," Helen whispered to Jim Preston. "Head for Linder's. Her father will be there by this time."

The boatman sensed the alarm in Helen's words and he jerked open the throttle of the _Liberty_ and sent the boat racing through the night. In less than five minutes they were slowing down for the pier. The lights of a car were at the sh.o.r.e end of the landing and someone with an electric torch was awaiting their arrival. It was Doctor Stevens, pacing along the planks of the landing stage.

"Have you found Margaret?" he cried as the _Liberty_ sidled up to the pier.

"Got her right here," replied Jim Preston, "but she's got a bad b.u.mp on her head."