The next two days following her visit to Cliffwood, Nancy Drew went about the house in a preoccupied state. Alternately quiet and talkative, she was never without an air of suppressed excitement.

In an attempt to strike a plausible explanation for the strange happenings at The Mansion, she reviewed every detail of the story related by the Turnbull sisters.

“It’s possible the shadows on the wall at night could have been caused by the wind blowing the trees,” she told herself. “Still, Rosemary is a practical woman and I’m sure she wouldn’t be frightened by a thing like that.”

Before she had visited The Mansion with Rosemary, Nancy had been inclined to suspect that someone was playing a practical joke on the Turnbull sisters, but the loss of the diamond bar pin made such a theory seem unlikely. Without doubt, someone had stolen the pin, but in what manner, she was unable to guess. Apparently, it had vanished into thin air.

The longer Nancy reflected on the mystery the more certain she was that a sinister hand was behind everything. However, she refrained from disclosing this thought to her father lest he reconsider his promise and refuse her permission to visit the old house during the week he was to spend in Chicago.

Carson Drew planned to leave on Thursday. Nancy had written a note to the Turnbull sisters telling them to expect her on Saturday morning. She had taken care not to mention the approaching visit to anyone save her father, and even Hannah Gruen was in ignorance concerning her plans.

On the day set for Mr. Drew’s departure, Nancy helped him pack his bag, and then shortly before train time took him to the railroad station in her roadster.

“When shall I expect you home?” Nancy inquired, as they stood on the platform waiting for the train.

“A week from today. If you would like me to, I’ll stop at Cliffwood on my return trip. Your story has aroused my interest, Nancy. I’m curious to have a look at that old stone mansion.”

“Oh, I wish you would stop for me,” Nancy declared enthusiastically. She glanced carefully about to see that no one was within hearing distance. “If I haven’t solved the mystery by that time you’ll help me, won’t you?”

“Of course I’ll do anything I can, but from what you’ve told me it sounds like a tough case. I’m not sure that I’ll be able to solve it myself. However, if you fail, I’ll try it.”

The conversation was cut short as a shrill whistle announced the approach of the train.

“I’ll telegraph you the exact hour of my arrival in Cliffwood,” he said hastily.

“The Turnbulls live some distance from the railroad station, so I’ll meet you in the car,” Nancy promised.

“And remember⁠—don’t run into danger.”

The heavy passenger train came pounding and clanging into the station, and Mr. Drew picked up his bag. Kissing Nancy goodbye, he made a dash for the Pullman cars, which were at the rear of the train, far down the track.

Nancy waited until the train pulled out and then slowly made her way back to the automobile. Now that her father had actually departed, she felt lonesome.

“I may as well stop at Helen Corning’s before I go home,” she decided as she stepped into the roadster. Helen Corning had been her chum for years.

Accordingly, she called at the home of her chum and was pleased to find her there. Helen promptly tempted her into a lively game of tennis, and before Nancy realized it, the afternoon was nearly gone.

“You must stay for dinner,” Helen urged. “It won’t be any fun eating at home all alone.”

“But Hannah is expecting me.”

“We can telephone her.”

“Oh, all right,” Nancy gave in.

Not only did she stay for dinner, but she remained during the evening, for Helen would not permit her to go.

“Remember the fun we had at Moon Lake last summer?” Helen asked her. “You know, I never did entirely forgive you for cheating me out of a share in your adventure. Why didn’t you tell me you were going to chase robbers that day when you left camp?”

“I didn’t know it myself then.”

“Well, if you ever stumble upon another mystery, I want you to take me in on it!”

Nancy was on the verge of telling Helen about her proposed trip to The Mansion, but she could not bring herself to the point of revealing the secret. Helen’s intentions were of the best, but she was a natural born gossip and Nancy doubted that it would be possible for her to keep the matter to herself.

“It might do a great deal of harm if it were rumored why I am leaving town,” she thought. “No, I’ll tell Helen after I return.”

It was late when Nancy reached home and the housekeeper had retired.

“I’m too sleepy to pack my bag tonight,” she decided as she locked the doors and windows. “I’ll do it the first thing in the morning.”

But in the morning there were other matters which claimed Nancy’s attention. She had promised the housekeeper a week’s vacation during her visit in Cliffwood, and before the house could be closed there were many things to be done. The entire day had slipped away almost before she realized it.

“Miss Nancy, if you don’t mind, I’ll go to a moving picture show with my sister,” the housekeeper said to her after the dinner dishes had been cleared away.

“Why, of course, Hannah,” she agreed generously. “I don’t mind in the least. I’ll be busy with my packing.”

As soon as Hannah had left the house, Nancy went directly to her room and began sorting out the dresses that she planned to take with her to The Mansion. It was ten minutes after eleven when she finished.

“There, I guess that’s all,” she decided. “Oh, no, I’ve forgotten the revolver Dad gave me. I must take that!”

She hurried downstairs and went directly to the desk where the revolver had been left. But with her hand on the drawer, Nancy hesitated.

Uneasily, she glanced about the room. For a reason she could not explain, she felt that someone was watching her.

“I guess my nerves are getting jumpy,” she thought. “I do wish Hannah would come home.”

Upon impulse, she moved toward the window. As she took a step forward, she thought she heard a step on the porch. Was it only imagination or was someone really prowling about the house?

Before she could make a move to investigate, the doorbell rang sharply.

Nancy started.

“It must be Hannah,” she assured herself. “Probably she forgot her key.”

But as she crossed the room she distinctly heard the steps creak under the weight of some person. Hesitating but an instant, she opened the door.

There was no one in sight. Wonderingly, Nancy stepped out upon the veranda and glanced up and down the street.

“That’s strange,” she murmured uncomfortably.

She went to the edge of the porch and peered in the direction of the hedge. Was it possible someone was hiding in the bushes? A careful survey disclosed no human form.

As she turned to go inside the house, her eyes fell upon a white envelope near the door. Curiously, Nancy picked it up and held it to the light.

“Why, it’s addressed to me!” she gasped in astonishment, as she made out the bold scrawl.

Hastily entering the house and closing the door behind her, Nancy Drew ripped open the envelope. As she scanned the note, the color faded from her face.

“An anonymous message!” she whispered. “Someone has sent me a threatening letter!”