"Whatever is it, mother?" asked Robin anxiously.  
For Mrs. Vaughan's face was quite pale with worry as she stood on the bank while they rowed towards her. "Don't pull right in," she said. "Though I suppose it doesn't matter out of doors. It's—— Better not, perhaps, under the circumstances. Stay there—on the water, and I'll talk to you from here."
 
"Why! What—ever——!" The eyes of the three grew large and round. Then an awful idea struck Peter. "Mother, you don't mean to say that anything's happened. You talk as though we'd got the Plague! Whatever is it?" He racked his brain to think of some possible horror. "Well, it isn't that the Lennoxes have wired to say that they can't come, for, if so——!"
 
"It's—worse." Mrs. Vaughan laughed ruefully. "One of them has arrived. It's—Dick; but—oh, he's covered with spots! Came out in the train, so he says; and, poor boy, he's feeling pretty bad, I think. It's certain to be something infectious, particularly as Donald—so Dick says—has been kept at home for a day or two, because this morning he woke up with a terrible headache, and wasn't well enough to travel."
 
"Measles! Well, we've had them!" said
 
Robin hopefully.
 
"So have they. I greatly fear that it's scarlet fever. The poor boy is terribly annoyed with himself for coming, but how could they think of such a thing as scarlet fever? No; I pity his mother—so far away—as much as I pity myself. I've sent for Dr. Greig, and, in the meantime, you had better all three stay over on the Island for tea. Get Gardener's wife to give you some, and explain to her. I'm so sorry, dears, that all this has just happened when you had planned such a happy time."
 
"Sorry for us! It's you—and Dick, of course," said Robin. "Cheero, mother; let us help. Scouts know all about First Aid!"
 
"So do Guides," added Jan quickly.
 
"First Aid is not needed for scarlet fever. None of you have had it, you know; and there's your exam. ahead, Robin. You can't run risks. No, I only called you to tell you; for you must keep out of the way till the Doctor's told me definitely what it is. I'll blow the horn again as soon as I've news." Their mother waved her hand and was gone.
 
"Wheww!" said Robin; and they rowed in silence to the other side of the water. In an instant their castle of hopes was in bits, and their holiday seemed spoilt. "If I wasn't a Scout I'd feel inclined to—jolly well——!" Peter vented his feelings in kicking up a huge clod of turf as he stepped ashore.
 
"And if I wasn't a Guide, I'd——" Jan's voice sounded pretty near to tears.
 
"No cousins—or as bad as none; perhaps worse, for Mother'll be worked to death," continued Peter; "all our ripping preparations spoilt! No camp——!"
 
"Steady on!" called Robin; he could have grumbled a bit himself, easily enough, but he wasn't going to. He had been thinking hard instead, and he broke out suddenly: "I've got an idea. No, I won't say what it is till I know if it's needed. Don't give up hopes of the camp yet, and let's go meanwhile and ask Brownie about tea."
 
The gardener's house, to which they turned their steps rather dejectedly, was a very old stone cottage, as old as the Chase itself. It had been used for generations as the home of one or other of the keepers, having been built in a convenient place, so it was said, for the operations of possible river-poachers to be watched. Old Brown the gardener, though he had been in the service of the family all his life, had only lived in the cottage for about fifteen years. With the fall of the family fortunes the outdoor as well as the indoor staff of the Chase had been reduced, and at present he was a regular handy-man, the only man, indeed, about the place. His wife welcomed the three comfortably enough; and under the soothing influence of Brownie's scones and home-made jam their spirits began to rise. By the time the "third cup" stage was reached they were able at last to unburden themselves to their kind-hearted listener.
 
"We'd expected such lots of fun when the Lennoxes came," said Peter.
 
"Sure, my dear," said Brownie, nodding commiseratingly.
 
"They're sure to be jolly, you see, being relations!" said Jan ingenuously; "and besides"—heedless of a warning touch from Robin, who didn't believe in talking over family matters, she went on confidingly—"we somehow hoped they might know what the mystery is. You know, Brownie, at least, but I don't suppose you've ever thought about it——"
 
"Have you?" asked Peter suddenly, as the old woman did not answer, but rose busily to poke the fire.
 
"Sure, my dear, and having been in service at the House before ever I married Brown——" began the old body a little confusedly.
 
"I say," Robin broke in, "look here, Jan and Peter. And, Brownie, I'm not sure——"
 
"There's the horn!" interrupted Peter suddenly. The clear sound came faintly over the water.
 
"Aye, the horn it is, sure enough," said Brownie in a relieved voice, "and hadn't you better be going to see?"
 
But she spoke to an empty kitchen: the three were gone. Down to the water's side they raced, and were just pushing off when their mother began to call to them. "You needn't come over; I can speak from here. Yes, it is what I feared. Dr. Greig says there's no mistake about it. And Donald says that there was a case in his form at school. Now, what I'm to do with you I don't know."
 
"Mother," began Robin, "listen; I know a tremendously good way out of the difficulty."
 
"What is it?" inquired Mrs. Vaughan.
 
"It's nothing more nor less than the camp!" said Robin; "and, if you'll stay there for an instant, I'll row over and tell you what I mean."