There followed whispered good-nights interspersed with giggles, and finally the five girls from dormitory "C" tiptoed across the hall, and, silent as mice, crept into their own room.

Quickly they undressed and slipped into their white nightgowns, listening breathlessly every once in a while for some sound that might tell of discovery.

None came, however; the big house was as silent as a tomb and Billie was just about to slip into bed when she happened to look out of the window.

The moon was bright, bathing the smooth lawn of Three Towers in a light almost as bright as day, so that Billie could not have been mistaken in what she saw.

A man ran quickly, furtively, across the lawn and disappeared in the shadow of the trees bordering the lake. Billie's heart amazingly skipped a beat and then stood still.

CHAPTER XVI

MYSTERY

For several minutes Billie Bradley stood at the window straining her eyes in the direction in which the man had disappeared, scarcely daring to breathe.

Then, when she was sure that whoever the fellow was he did not intend to come back, she turned from the window with a little sigh of mingled excitement and relief.

It was only a sigh, but it sounded so loud in the stillness of the room that it suddenly brought Billie to her senses.

Shivering a little, she crept into bed and drew the covers up under her chin. It would never do to be discovered by Miss Ada at this last minute, and she certainly could not do any good by standing there staring out of the window.

Whoever the man was, he had gone now and would not return. But could she be sure of that? Suppose he had been a thief--she shivered and drew the covers over her head. In that case she should have roused Miss Ada and told her the story.

But then, Miss Ada's first question was sure to be, "How did you happen to be standing by the window at twelve o'clock at night?"

Then would come suspicion, a search, perhaps, and discovery. No, she couldn't, she couldn't! But what had that man been doing?

For more than an hour she lay, too excited to sleep, shivering at any sudden sound, wondering--wondering. Toward morning she fell asleep, only to dream of picnics where one did nothing but catch codfish and eat them, of a strange man with a stooping figure, running across a lawn bathed in moonlight.

Luckily for the girls who had been at the party, there were other girls in dormitory "C" who had gone to bed at the usual respectable hour--Amanda Peabody and Eliza Dilks, for instance--and who, as usual, heard the rising bell. If it had not been for them and the noise they made Billie and the others of the five might have slept on till noon.

As it was, they rose resentfully, finding it hard to get their eyes open, looking for their clothes half-heartedly, grumbling at everything and everybody.

It was Billie, who had slept less than any of them, who whispered a warning to them. She had seen Eliza and Amanda eyeing them suspiciously.

It would never do, after having managed the party so successfully, to let the cat out of the bag after the affair was over.

The argument appealed to the girls, and they woke up with a suddenness almost more suspicious than their former sleepiness had been.

It was not till noon that Billie found a chance to tell the girls what she had seen from the dormitory window after the rest of them were in bed.

By that time the last evidence of last night's party had been cleared away, and the girls were beginning to feel secure again.

One by one they had run back to the dormitories between cla.s.ses, made the remnants of the feast into small paper bundles, and had smuggled them down to the cellar and deposited them in the big box where all the papers and other rubbish was kept until the man of all work about Three Towers carted it off into the woods to be burnt up.

So now, in hilarious spirits, they answered Billie's call and flung themselves in various characteristic and joyful att.i.tudes upon her bed.

"Speak, woman, speak," Laura commanded her, stealing a chocolate from Vi's sweater pocket. "What have you got to say for yourself?"

"Yes, what do you mean by getting up such a disgraceful affair as happened here last night?" added Nellie Bane in such an exact imitation of Miss Ada's manner that the girls giggled delightedly.

"Look out," cried Connie Danvers, in a whisper, for Amanda and the "Shadow" had just come into the room. "If you are not careful our wicked plot will yet be discovered."

"What is it you wanted to say, Billie?" asked Caroline in her matter-of-fact tone. "If it's anything very private, I guess we'd better move."

Caroline had been thinking about Rose and the happening of the night before--thinking till her head ached--but she had not yet decided what to do about it. As for Rose--her head ached, too--she knew what she was going to do about it. Some way or other she was going to get even with Billie! And Caroline, too, big snooping, spectacled thing!

"It isn't a bit private," said Billie, looking so serious that the girls suddenly became serious too. "It was about something I saw last night after----" she was about to say "after the party," but as Amanda and her "Shadow" had come dangerously near and were listening with all their ears, she decided not to.

"Well, what was it you saw?" the girls demanded impatiently, as she hesitated.

Billie lowered her voice and spoke hurriedly.

"I saw him going across the lawn. He was running, and while I watched he disappeared among the trees near the lake."

"A man?" asked Vi while the others stared.

"Of course," Billie nodded impatiently. "What did you think it was--a grizzly bear?"

"It might have bees from your description," Vi retorted, but right here the girls broke in with a running fire of questions and Billie was kept busy trying to answer them all at once.

"But, Billie, why didn't you tell somebody?" Vi asked, but Laura crushed her with a look.

"Tell somebody?" she repeated scornfully. "How could she and give the whole----"

But this time it was Laura who suddenly came to a standstill, the reason being a vicious little pinch from Billie in the fleshy part of her arm.

"Hush!" she whispered fiercely while all the girls looked alarmed.

"Haven't you any sense at all?"

And Laura, feeling very sheepish, did not even answer back. For Amanda and the "Shadow" were still making excuses to hang around.

"But, Billie, what are we going to do about it?" asked Connie nervously.

"Yes, we don't want funny looking men wandering around our campus at night," said Rose, lazily straightening a ruffle on her dress.

"No, nor in the day time either," said Nellie, looking fierce.

"Well, you all needn't look at me as if it were my fault," said Billie plaintively. "I certainly didn't ask him to come and keep me awake all the rest of the night."

"But n.o.body's answered my question," Connie objected. "I want to know what we're going to do about it."

"Why, there's nothing to do about it," said Billie. "I suppose all we can do is to wait till we see him again--if we do--and then tell Miss Walters about it."

At that moment the gong rang and hands flew to straightening hair and belts and ruffles preparatory to starting the afternoon cla.s.ses.