Silver on the Tree by Susan Cooper

“you can tell us what we’ll see when we get to the top of the ridge.”
    Barney turned, flipping his blonde forelock out of his eyes, and stared up the mountain, over the bracken and the green slope. He said nothing.
    â€œAnother ridge,” Jane said cheerfully. “And from that one you’ll see another.”
    â€œWhat’ll we see, Barney?” Simon persisted. “Cader Idris? Snowdon? Ireland?”
    Barney looked at him for a long blank moment, his eyes empty. He said at last, “Someone.”
    â€œSomeone? Who?”
    â€œI don’t know.” He jumped up suddenly. “If we sit here all day we’ll never find out, will we? Race you!”
    He leapt up off the slope, and in an instant Simon was bounding confidently after him. Jane watched them, grinning. In the last year or so, though her younger brother had remained fairly neat and small, Simon seemed to have sprouted legs far too long for his body, like a giraffe. There were very few family races now that he failed to win.
    Both boys had disappeared above her. The sun was hot on the back of her neck, as she climbed slowly after them. She stumbled on an outcrop of rock, and paused. Somewhere far away on the mountain a tractor’s engine purred; a pipit shrilled overhead. The rocky outcrops led to the top of the ridge here in an erratic progression, through bracken and gorse and billowing piles of heather; hare-bells starred the low sheep-cropped grass, and little creeping white flowers she did not recognise. Far, far below, the road wound like a thread past the dune-fringed golf course, and the first grey roofs of Aberdyfi village. Jane shivered suddenly, with a sense of being very much alone.
    â€œSimon!” she called. “Barney!”
    There was no answer. The birds sang. The sun beat down out of a lightly-hazed blue sky; nothing moved anywhere. Then very faintly Jane heard a strange long musical note. High and clear, it was like the call of a hunting horn, and yet not so harsh or demanding. It came again, closer. Jane found that she smiled as she listened; it was a lovely beckoning sound, and suddenly she was filled with an urgent desire to find out where it came from, what instrument could play so beautiful a note. She went on more swiftly up the hillside, until all at once she was over a last rocky edge and could see before her the first few yards of the ridge of the hill. The long sweet note came again, and on the highest grey granite outcropping that met the sky, she saw a boy, lowering from his lips the small curved horn with which he had just blown a call over the mountains, out into nowhere. His face was turned away from Jane, and she could see little except that he had longish straight hair. Then as he moved one hand in an automatic swift gesture to push back the hair from his forehead, she knew suddenly and positively that she had seen that gesture before, and knew who this boy was.
    She went forward up the last slope to the rock, and he saw her and stood waiting.
    Jane said, “Will Stanton!”
    â€œHello, Jane Drew,” he said.
    â€œOh!”
Jane said happily. Then she paused, surveying him. “I can’t think why I’m not more surprised,” she said. “The last time I saw you was when we left you on Platform Four at Paddington Station. A year ago. More. What are you doing on the top of a mountain in Wales, for goodness’ sake?”
    â€œCalling,” Will said.
    Jane looked at him for a long moment full of remembering, thinking back to a dark adventure in a beleaguered Cornish village, where her Great-Uncle Merriman had brought her and Simon and Barney together with an unremarkable round-faced, straight-haired Buckinghamshire boy—who had seemed to her in the end as alarming and yet as reassuring as Merriman himself.
    â€œDifferent, I said you were then,” she said.
    Will said gently, “You three are not altogether ordinary, as you very well