Maud did show up later and went to the dining room with the group. Nancy asked John if he had been rewarded in his sleuthing.

He shook his head. "I saw no 'sharks," and no one here admits to having used the canoe."

This reminded Nancy of the fisherman she had seen on the river. Because of his hat, she had not been able to tell if his hair was crew cut. But she wondered if he might be the man Helen had seen after the girls' canoe had capsized.

At the supper table Nancy confided this idea to her friend in a low tone. Helen wrinkled her brow. "From the general impression I had of Mr. Crew Cut, Nancy, he could be the same one. But of course I only saw him from a distance."

Both girls became aware that Maud was eying them closely. "Planning another skin-diving excursion, Nancy?" the woman asked sarcastically.

Mrs. Willoughby hurriedly put in, "Oh, yes. I told Maud the latest-er-troubles."

"I should hope so!" Maud said sharply. "If there are dangerous people lurking around here, I'd like to be warned."

"Nancy's the one in danger," Emily reminded Maud coldly.

To change the subject, Nancy observed, "The new waitress, Jean Holmes, seems to be very efficient."

Maud tossed her head. "I do have an instinct about people, you know." But she was clearly pleased at Nancy's remark.

After supper Nancy was leaving the room with the others when Anna came up behind her. "I have some information for you, Miss Drew," the waitress whispered. "Mary Mason mostly kept to herself, but Kitty, one of the girls, thinks Mary commuted to Dockville every night. She also remembers that Mary once worked for a Mrs. Ernest Stonewell in River Heights."

"You're very helpful, Anna," Nancy said. "Thank you."

Nancy went to the hall desk and picked up a telephone directory. There were several Masons listed in Dockville, which was near River Heights. The young sleuth dialed the number of each Mason. n.o.body knew Mary, the waitress. Nancy now looked up Mrs. Ernest Stonewell's address.

"I'll call her tomorrow."

The rest of the evening Nancy spent playing a lively game of ping-pong with Helen, Emily, and John. Around eleven o'clock everyone said good night. John walked with the two girls to their cottage and warned them to secure the new inside bolt on the door, as well as the bathroom window. "I'm within calling distance if you need me." He smiled.

"Thanks, John," said Nancy. "Every window sill in the bedroom will have a book on it. If any intruder tries getting in, I hope he won't notice the book, and will knock it off and wake us!"

Before going to sleep, Nancy thought happily that her father would soon be home. How much she had to tell him!

Helen, in the meantime, was wide awake. She tossed and turned restlessly. Finally, at midnight, she got up and put on her bathrobe and slippers.

"Maybe some fresh air will help me sleep," Helen thought.

Despite John's warning, she slid the bolt and left the cottage, closing the door quietly. The grounds were dark and silent. Helen turned toward the lilac grove.

Suddenly she saw a flickering light ahead, near the grove. Curious, she drew closer. A veiled figure with black hair and wearing a glowing white gown confronted her. The next instant Helen was struck on the back of her head and fell unconscious!

CHAPTER IX.

The Search BACK in the cottage, Nancy was awakened by an insistent ticking. She sat up and glanced in annoyance at her alarm clock. It certainly seemed noisy.

Suddenly Nancy realized that her friend's bed was empty. "Helen?" she called, thinking that perhaps the other girl had gone to get a gla.s.s of water. There was no reply.

"Where can Helen be at one-thirty in the morning?" Nancy asked herself. Hurriedly she put on robe and slippers and picked up her flashlight. When she found the front door of the cottage unbolted, she felt a pang of alarm.

Outside, Nancy searched the cottage area, calling her friend's name again and again. No response. Finally, thoroughly alarmed, Nancy decided to ask John for help. She knocked on his door. No answer. Perplexed, Nancy was about to leave when a twig crackled a short distance away. She turned off her flashlight and crouched behind a low shrub. Who was approaching? She was relieved a moment later to discern the familiar outline of John.

"Oh, thank goodness!" Nancy exclaimed, hurrying toward him. "Have you seen Helen?" she asked. "I woke up and found her gone."

"No, I haven't seen her," John replied. "I couldn't sleep so I walked down the road. Come on. We'll both look."

They started across the lawn.

"Let's check the inn first," Nancy proposed. "Maybe Helen's there."

The grounds seemed eerie in the moonless night as the couple walked quietly, beaming their flashes ahead of them. They circled the inn. The place was completely dark, with the exception of the tiny night light in the main lobby.

Nancy suggested they try all the doors. "If one is unlocked, it may mean Helen is inside."

The front, rear, patio, and kitchen doors were securely bolted from the inside.

"Perhaps Helen couldn't sleep and went for a walk near the river," John suggested.

Quickly he and Nancy went to the waterfront. Starting with the area near the dock, they proceeded along the bank, calling Helen's name. As they came to the lilac grove, John said: "I don't think-"

He was interrupted by a low moan which came from beyond a lilac bush. The couple hurried toward it, with Nancy focusing the beam of her flashlight on the ground.

"Helen!" she exclaimed in horror.

Before them lay her friend, unconscious.

Quickly Nancy and John knelt beside Helen. John held the flashlight while Nancy made a rapid examination. Helen's pulse was normal, but there was an ugly lump on the back of her head.

John looked grim as Nancy chafed Helen's wrists. "She must have been struck by a blunt instrument," he said.

Helen's eyelids flickered open. For a moment the girl looked terrified, then smiled feebly as she recognized John and Nancy.

"Wh-what happened?" she murmured.

"Don't talk," Nancy said soothingly, but Helen insisted upon sitting up.

"Oh, my head!" she groaned, and leaned against Nancy.

A few minutes later the injured girl was able to talk. She explained about leaving the cabin and walking toward the lilac grove, then told of the strange figure in white she had seen.

Helen described the long translucent robe the figure had worn. "The last thing I saw was that ghostly figure waving her arms back and forth, as if signaling to someone. Then I was struck on the head and blacked out."

"Don't talk any more now," said John, as Helen sighed wearily. "We'll go back to the cottage and Nancy will put you to bed."

John carried Helen, and with Nancy's guiding light, headed toward the cottage. They had hardly started when the trio was startled by a loud boo-oo-m! It seemed to come from the direction of the cottages!

"That sounded like an explosion!" cried Nancy. She broke into a run.

John, carrying Helen, followed as fast as he could. A moment later Nancy heard a crackling noise and smelled smoke.

"John!" Nancy cried in horror. "Look! Our cottage is on fire!"

The young people stared ahead in dismay. Tongues of orange-red flames were indeed shooting upward from the girls' cottage! The trio could already feel the heat from the blaze.

"We'll have to douse it," John said tensely. "The whole row will burn down if we wait for the fire department."

Helen insisted she was strong enough to walk. "I can help!"

John raced to the side of the inn where an extension water hose was attached. "Get the buckets near the kitchen door!" he shouted to the girls.

They dashed toward the inn. At the same time, the hall lights came on and the front door was flung open. Emily, Maud, and Mrs. Willoughby, dressed in robes, rushed out. Behind them was Mr. Daly, carrying a Revolutionary War musket!

Each group was amazed to see the other but Nancy took no time asking questions. "Our cottage is on fire!" she announced.

Soon everyone joined in tossing bucket after bucket of water from a garden spigot onto the blaze. John played a steady stream from the hose. Gradually the blaze was reduced to embers.

"Glad we saved the other units, anyhow," John said, glancing at the ruined guest cottage. "Too bad you girls lost all your clothes."

"But saved our lives by not being in the cottage," Nancy remarked grimly.

"How did the fire start? What caused that explosion?" Emily asked, explaining that she and the others had been awakened by the noise.

"I believe," Nancy said gravely, "it was caused by a time bomb which someone placed in our cottage before we went to bed. A ticking sound woke me. I thought it was my clock."

Her listeners were shocked. Mrs. Willoughby grew deathly pale, as Maud shrilled, "There must be a lunatic loose around here."

For once Nancy was inclined to agree with her. The young sleuth added that of course nothing could be determined until daylight when the ruins would be examined.

The exhausted group went back to the inn. "Nancy and Helen," Emily said, "I feel terrible about this whole thing."

Mrs. Willoughby, too, expressed her regret. "At least some of the loss will be covered by our fire insurance," she added.

Nancy smiled and nodded, then started to relate Helen's startling experience just before the fire.

When Nancy came to the part about the woman in the white robe, Emily shivered. "I don't believe in ghosts," she averred, "but Mary Mason probably saw this person. That's why she said Lilac Inn was haunted!"

Nancy suddenly noticed how pale Helen was and suggested she get to bed at once.

"Oh, yes," said Emily. "Nancy and Helen, take the front second-floor bedroom."

Nancy noticed that Mr. Daly still clutched the ancient musket. With a sheepish smile, he said, "Shortly before the explosion, I thought I heard someone prowling around outside. I grabbed this old musket-guess it's been here since the inn was built. It's not loaded, but I figured it might scare away an intruder."

John grinned. "Nancy and I were your 'prowlers.' " He explained that they had tried all the doors in their search for Helen.

The women and girls started upstairs. John and Mr. Daly, carrying his musket, said they would "stand guard" for the rest of the night.

As Emily showed Nancy and Helen to their room, she said firmly, "This awful experience has made me decide to call the police first thing in the morning!"

"Oh, Emily, thank goodness!" Helen exclaimed in relief. "If there is some kind of maniac loose at Lilac Inn, you'll be doing the right thing."

Emily stepped closer to the girls. "When the police arrive," she whispered, "I'd appreciate it if you still don't mention the diamond theft."

Her friends, though surprised, promised not to say a word about it.

"You see," Emily went on softly, "it's not for my sake, but Aunt Hazel's. I can't explain any more right now. You go to bed. I'll call you if I need you."

Nancy and Helen were too polite to ask further questions. Nevertheless, Nancy fell asleep wondering about Emily's request. When the young sleuth awoke in the morning, her first thought was of the bomb. When had it been planted? While she was skin diving?

"The person who placed the bomb might have been seen by someone connected with the inn," Nancy speculated.

Helen awoke just then, and Nancy asked how she felt. "Fine, except for a slight headache." Helen shuddered. "Last night seems like a terrible dream!"

A few minutes later Emily knocked on the door with clothes for Helen and Nancy to borrow. While they dressed, she reported that a trooper from the Benton State Police Barracks would be over shortly to inspect the burned cottage.

"John checked the lilac grove at daybreak," she added. "There were lots of footprints of various sizes, but no sign of any suspicious person."

"Maybe I was dreaming I saw the ghost," Helen said. She felt the back of her head. "But this b.u.mp is real!"

The three girls went down to breakfast. John, Mrs. Willoughby, and Maud were already at the table. No other guests were in the room. Nancy gave her order to Anna.

At a nearby table the waitress Jean Holmes was arranging flowers in a copper vase. The girl smiled shyly at Nancy, picked up the bowl, and walked toward the bay window. As she started to place the flowers on the wide sill, Jean gave a startled cry. She dropped the bowl, scattering flowers and water on the floor.

Everyone at the table stared out the window. Two men were peering in. Nancy recognized them and jumped to her feet in surprise.

CHAPTER X.

"Blue Pipes"

THE unexpected sight of the two men peering through the dining-room window had startled Nancy, but in a happy way. She recognized the observers as her father and the state trooper, Lieutenant Brice.

As Jean apologized for her clumsiness and went to the kitchen for her broom and mop, Nancy hurried to the hall. She greeted her tall, handsome father and the officer who had come to her rescue when her car was forced into the ditch.

"Nancy, are you all right?" was Carson Drew's first question.

"Oh, just fine, Dad. What a nice surprise to see you!" She kissed him affectionately. With a smile she added, "I didn't expect to see you again so soon, Lieutenant Brice."

The officer grinned. He explained that he had been a.s.signed to investigate the cottage fire. When he arrived at Lilac Inn, he had met Carson Drew, who had just driven up. The two men were completing a quick tour of the grounds when they pa.s.sed the dining room and looked in.