"Was it a threat?" George demanded.
Nancy nodded. "I"ve been ordered to get rid of the black mask I picked up at Gloria"s home."
"Oh, Nancy!" Bess exclaimed. "Didn"t I tell you? Why did you ever keep the mask?"
"I intend to hold on to it until the police ask me for it."
"Good for you, Nancy!" George approved. "Don"t let that man bluff you!"
Bess sighed. "Well, if you"re not afraid, I guess we may as well run along. It"s getting late. But do be careful, Nancy."
After the girls had gone, Nancy locked the screen door, but left the front door open, for the night was very warm.
She sat for a while in the living room, thinking about the new developments in the case. Then, abruptly, she went to a desk drawer and took out the black hooded mask.
As she was gazing at it, Mrs. Gruen came downstairs from her room.
"Nancy, I think you should go to bed," she remarked. Then noticing the mask in the girl"s hand, she added with a shudder, "Mooning over that sinister thing again?"
"It"s my most valuable clue! This might be the very thing I need to track down the thieves."
Nancy revealed to the housekeeper that she had been ordered to get rid of the mask.
"Well, obey their orders. I heard you telling Bess and George about your adventure tonight. The whole thing sounds dangerous to me."
"Now, Hannah, don"t get so upset. Please. You know when I"m caught in a tight spot I can usually manage to get out of it."
"Just you wait, Nancy Drew. Someday you won"t be able to find a way out. I worry all the time about you and your father. Two of a kind!"
"Well, then," Nancy replied, "there"s no need to worry if I"m like Dad. He has never failed to crack a tough case!"
The housekeeper realized that it was futile to urge Nancy to stop work on a mystery, once she had started.
"What is it now, Nancy? Why are you staring so hard at that mask?" Hannah asked.
"It just occurred to me," Nancy replied, "that the thief must have a good reason why he wants this returned. Perhaps it contains some clue he doesn"t want me to find."
While Mrs. Gruen watched, Nancy ripped out the white silk lining of the velvet mask. To her disappointment, nothing had been hidden inside.
"I guess I was wrong," she admitted ruefully. "I thought jewels or something valuable might have been tucked under the padding."
"I"ll sew the lining back in," the housekeeper offered. "Not tonight, though. I"m too sleepy."
As Nancy started to tuck the lining back in, she noticed some numbers written on the reverse side.
"What"s this?" she said.
Carrying it to a brighter light, Nancy studied the numbers. They read: 621 626 628 71 75.
"What do they mean?" Mrs. Gruen asked.
"I wish I knew," Nancy replied.
"The ink appears fairly fresh," Mrs. Gruen remarked. "Not faded as it would be if the cloth were old."
"The numbers may be a code. I wonder-"
At that moment the telephone rang and Nancy hastened to answer it. This time it was her father.
"I"m so glad to hear from you. How"s everything?" Nancy asked cheerily.
"Fine on this end.How about you?"
She reported what she had been doing on the case, then told him of the numbers on the mask"s lining.
"The numbers may be a code," Nancy said
"Read them to me," Mr. Drew suggested.
After Nancy did so, he said, "Very interesting. They sound like dates."
"You mean 621 is June twenty-first?"
"Yes. And the last one"s the day after the Fourth of July."
"Oh, Dad, you"re wonderful! That"s probably exactly what they are-dates for planned thefts! The woman in the Javanese costume put them in, or someone wrote them down before giving her the mask so she wouldn"t forget them."
"Nancy, here"s a suggestion. Call the Lightner Entertainment Company in the morning and find out if they coincide with parties they"re arranging. But be discreet in asking questions."
"I will!" Nancy a.s.sured him. "And Dad, when are you coming home?"
Mr. Drew said that unless something unexpected came up he would return the following evening.
"We miss you," she said. "By the way, you"re at the Excelsior in Amstar, aren"t you?"
As Nancy said good-by she heard a sound on the front porch. Thinking someone was arriving, she went to look out, but no one was there.
"My imagination, I guess," she decided. She closed and locked the front door, then went up to bed.
Nancy telephoned Linda Seeley at nine o"clock the following morning. After explaining where she had obtained the dates, she asked if Lightner"s had any parties scheduled for them.
"Yes, we do have for the first three you mentioned," Linda answered without hesitation. "I know, because I"ve worked on them myself. Wait, I"ll check the others."
In a moment she returned to say that July first was on their books, but the office had no record of a party for the fifth.
"I"ll contact the social editor of the newspaper," Nancy said. "Someone may be giving a big party without Lightner"s services."
"Nancy, if you"re still working on the theft, you"d better be wary," Linda advised hurriedly. "After what happened last night at the reception, I"m getting scared."