The guard reminded Albert Watson that he had not revealed why he was sneaking along the ground.
"Well," the prisoner said, "it was because of you. I heard downtown that there was a detective patrolling this place and I didn't want to bump into you. I was afraid of just what did happen."
The man relaxed a little. "I guess you're a pretty good guard at that."
Detective Patrick let go of Albert Watson's arm. "Your story sounds okay, but we'll go in the house and do some telephoning to find out if you're telling the truth."
"You'll find out all right. Why, I'm even a notary public! They don't give a notary's license to dishonest folks!" the trespasser insisted, Then he stared at Nancy and Helen, "What are you doing in those funny clothes?"
"We—are—we were having a little costume party," Helen responded. In the excitement she and Nancy had forgotten what they were wearing!
The two girls started for the house, with the men following. When Mr. Watson and the guard saw Miss Flora and Aunt Rosemary also in costume they gazed at the women in amusement.
Nancy introduced Mr. Watson. Miss Flora said she knew of him, although she had never met the man. Two phone calls by the guard confirmed Watson's story. In a little while his wife arrived at Twin Elms to drive her husband home, and Detective Patrick went back to his guard duty.
Aunt Rosemary then turned out all the lights on the first floor and she, Miss Flora, and the girls went upstairs. Bedroom doors were locked, and everyone hoped there would be no disturbance during the night
"It was a good day, Nancy," said Helen, yawning, as she climbed into bed.
"Yes, it was," said Nancy. "Of course, I'm a little disappointed that we aren't farther along solving the mystery but maybe by this time tomorrow—" She looked toward Helen who did not answer. She was already sound asleep.
Nancy herself was under the covers a few minutes later. She lay staring at the ceiling, going over the various events of the past two days. As her mind recalled the scene in the attic when they were pulling costumes from the old trunk, she suddenly gave a start.
"That section of wall back of the trunk!" she told herself. "The paneling looked different somehow from the rest of the attic wall. Maybe it's movable and leads to a secret exit! Tomorrow I'll find out!"
CHAPTER XThe Midnight Watch
As SOON as the two girls awoke the next morning, Nancy told Helen her plan.
"I'm with you," said Helen. "Oh, I do wish we could solve the mystery of the ghost! I'm afraid that it's beginning to affect Miss Flora's health and yet she won't leave Twin Elms."
"Maybe we can get Aunt Rosemary to keep her in the garden most of the day," Nancy suggested. "It's perfectly beautiful outside. We might even serve lunch under the trees."
"I'm sure they'd love that," said Helen. "As soon as we get downstairs, let's propose it."
Both women liked the suggestion. Aunt Rosemary had guessed their strategy and was appreciative of it.
"I'll wash and dry the dishes," Nancy offered when breakfast was over. "Miss Flora, why don't you and Aunt Rosemary go outside right now and take advantage of this lovely sunshine?"
The frail, elderly woman smiled. There were deep circles under her eyes, indicating that she had had a sleepless night.
"And I'll run the vacuum cleaner around and dust this first floor in less than half an hour," Helen said merrily.
Her relatives caught the spirit of her enthusiasm and Miss Flora remarked, "I wish you girls lived here all the time. Despite our troubles, you have brought a feeling of gaiety back into our lives."
Both girls smiled at the compliment. As soon as the two women had gone outdoors, the girls set to work with a will. At the end of the allotted half hour, the first floor of the mansion was spotless. Nancy and Helen next went to the second floor, quickly made the beds, and tidied the bathrooms.
"And now for that ghost!" said Helen, brandishing her flashlight.
Nancy took her own from a bureau drawer.
"Let's see if we can figure out how to climb these attic stairs without making them creak," Nancy suggested. "Knowing how may come in handy some time."
This presented a real challenge. Every inch of each step was tried before the girls finally worked out a pattern to follow in ascending the stairway noiselessly.
Helen laughed, "This will certainly be a memory test, Nancy. I'll rehearse our directions. First step, put your foot to the left near the wall. Second step, right center. Third step, against the right wall. I'll need three feet to do that!"
Nancy laughed too. "For myself, I think I'll skip the second step. Let's see. On the fourth and fifth it's all right to step in the center, but on the sixth you hug the left wall, on the seventh, the right wall—"
Helen interrupted. "But if you step on the eighth any place, it will creak. So you skip it."
"Nine, ten, and eleven are okay," Nancy recalled. "But from there to fifteen at the top we're in trouble."
"Let's see if I remember," said Helen. "On twelve, you go left, then right, then right again. How can you do that without a jump and losing your balance and tumbling down?"
"How about skipping fourteen and then stretching as far as you can to reach the top one at the left where it doesn't squeak," Nancy replied. "Let's go!"
She and Helen went back to the second floor and began what was meant to be a silent ascent. But both of them made so many mistakes at first the creaking was terrific. Finally, however, the girls had the silent spots memorized perfectly and went up noiselessly.
Nancy clicked on her flashlight and swung it onto the nearest wood-paneled wall. Helen stared at it, then remarked, "This isn't made of long panels from ceiling to floor. It's built of small pieces."
"That's right," said Nancy. "But see if you don't agree with me that the spot back of the costume trunk near the chimney looks a little different. The grain doesn't match the other wood."
The girls crossed the attic and Nancy beamed her flashlight over the suspected paneling.
"It does look different," Helen said. "This could be a door, I suppose. But there's no knob or other hardware on it." She ran her finger over a section just above the floor, following the cracks at the edge of a four-by-two-and-a-half-foot space.
"If it's a secret door," said Nancy, "the knob is on the other side."
"How are we going to open it?" Helen questioned.
"We might try prying the door open," Nancy proposed. "But first I want to test it."
She tapped the entire panel with her knuckles. A look of disappointment came over her face. "There's certainly no hollow space behind it," she said.
"Let's make sure," said Helen. "Suppose I go downstairs and get a screw driver and hammer? We'll see what happens when we drive the screw driver through this crack."
"Good idea, Helen."
While she was gone, Nancy inspected the rest of the attic walls and floor. She did not find another spot which seemed suspicious. By this time Helen had returned with the tools. Inserting the screw driver into one of the cracks, she began to pound on the handle of it with the hammer.
Nancy watched hopefully. The screw driver went through the crack very easily but immediately met an obstruction on the other side. Helen pulled the screw driver out. "Nancy, you try your luck."