"It'll be an awfully long day," said Robin.  
"Yes," said Peter and Jan.
 
"We'd better do something then," said Robin.
 
"Yes," said Peter and Jan again.
 
But it was difficult to know exactly what to do! For to-day was the day on which the Lennox cousins were to arrive—Dick and Donald, who had been invited to spend the last weeks of the holidays with the Vaughans. The Vaughans had been looking forward to this day immensely, but now it had come at last they felt that they could hardly get through the hours before their visitors would actually arrive. There would be "tons of things," as Peter said, "to do then," but there seemed nothing to do to-day.
 
"Let's go over to the Island," said Robin at last.
 
The island lay in the middle of the river that flowed at the bottom of the Vaughans' garden; it was only the work of a few minutes to pull across to the wooded little place where Brown the gardener had his cottage, but where, otherwise, the birds had it pretty much to themselves, as Jan said.
 
For the Vaughans were tremendously hard workers; Robin was entered for his first real exam.; Peter and Jan were each head of their forms at their respective schools, and "meant to keep head." Thus the Island certainly was left to the birds except in the holidays; but—a holiday camp was to be one of the tremendous pleasures ahead when the Lennoxes came.
 
"For they're Scouts, you see, like us, so they're sure to be keen," Robin had said, in appealing to his mother.
 
"It'll be such awfully good practice," Peter had gone on.
 
"And, as I'm a Guide——!" Jan had begun.
 
Mrs. Vaughan had laughed; she was a "jolly good mother for Scouts and Guides to have," as the boys and girls declared, because "she never fussed." She trusted them and left them to themselves, so that they might learn "self-reliance," as she told them. After she had laughed, however, on this occasion she shook her head. "I have no objection to your camping out for a night or two," she said. "After all, Robin camped with his troop last year, and the holiday won't have done much for him if he can't captain the rest of you over on the Island, but——"
 
"Oh, Mother!" said Jan, who guessed what was coming.
 
"Yes, I won't have Jan sleeping out of doors. Pneumonia two years ago, you remember, Jan? Or perhaps you don't,—you were too small; but—I do! No, Jan may choose either to sleep at home and join the boys by day, or—" Mrs. Vaughan wrinkled her brow—"perhaps Gardener's wife, Mrs. Brown, has a spare room. Yes, of course she has. Now, Jan, would you feel more on the spot and more of a regular camper if I could arrange for you to sleep in the Island Cottage?" "Oh, yes." Jan's eyes sparkled with delight.
 
"And the Lennox boys are Scouts too, so they'll be willing enough, I've no doubt," went on Mrs. Vaughan. "In fact I mentioned something of the plan to your aunt, and she seemed very pleased. Well, I think it can be arranged, but—it would be well to wait for really settled weather, wouldn't it?"
 
"The wind's in a good quarter now," Peter had said.
 
That had been yesterday, and the Lennoxes were coming in a few hours. It had been decided, though, that for a day or two the newcomers should sleep at the Chase and be introduced to the interests that the house and garden afforded. "You must remember," as Mrs. Vaughan told the children, "everything will be new and interesting to them. It is the first time they have been to the Chase, and the house will mean a good deal to them as belonging to their mother's family for so many generations. They may not want to camp out just at once, and——"
 
"It's queer, isn't it?" said Peter to the others as they made their way over to the Island, "to think that they've never yet seen the house, though Father is their uncle, and everything!"
 
"That's because they've always lived so far north," said Robin, "though it isn't as though the Chase is as it used to be, then—in the old days I mean. They'll understand that, though; they must have heard——" he sighed. "It must have been rippingly jolly," he said, "to live here in the old days."
 
"It is—now," said Jan loyally; but she and Peter knew what Robin meant. For the Chase had been the home of the Vaughan family for generations; it was an old rambling place standing in large grounds, but, ever since the children could remember, most of the house had been shut up and empty. Stories of the old days when their father and his sister had been young—before the change of fortunes had come which had made everything so different—were interesting to hear, if a little strange to understand.
 
"I often wonder," said Jan, when they were making their way across to the Island for another look at the camping ground on which they had fixed, "exactly what the mystery was."
 
"I do, too. But Dad never told us. When War's over, and he's back, perhaps he will. We'll be older," said Robin. "It's—a family secret, something to do with something that happened. It killed Grandfather, I believe. He died of a broken heart, or something. There was lots of money to pay, too, and—the Chase has been pretty nearly all shut up ever since, but——"
 
"I think it's strange," said Jan, "and I think it'd be better to tell us. We might help, you know. Oh, of course I know we all work frightfully hard at school because we're to bring back the family fortunes, but there are things I want to know about. There's a gap in the gallery where a picture's been taken down,—in between the portraits of Dad and Aunt Agnes when they were children,—Mother wouldn't tell me why. Not that I'd ask again, but——"
 
"Perhaps the Lennoxes will know," suggested Peter.
 
"If they do, I'm not sure that we ought ——" Robin was beginning when the sound of a horn was heard. It was Mrs. Vaughan's signal to the children when they were on the Island that they were wanted at once at home. At its sound the three turned their steps back to the boat, and in a few minutes Robin and Peter were pulling across. "Oh, my dears," said their Mother, standing on the opposite bank, her face quite pale with anxiety, "such an unexpected thing has happened!"