But Mary was still rebellious. She wasn't interested in Tom or even in baked potatoes. She wanted Macbeth.

"We'd better take care that Mrs. Thurston doesn't come up the valley again and find us," David said. "We're making enough noise for her to hear us from Witchend. We need a look-out. What about you, Mary? Will you go up and report?"

"He's too small and lonely for me to see him from up there," she protested, "but I'll try."

They pushed her up, and rather gloomily she admitted that she could see a long way. Meanwhile, Peter filled the kettle and built up the fire, Dickie went off whistling into the wood for more fuel, while David sorted out potatoes.

Suddenly Mary squeaked. "Be quiet, all of you. I can see them."

David swung himself up beside her, calling as he did so: "Stop the fire smoking too much, Peter. Well done, Mary. Now show me."

She pointed down to Witchend and David saw his mother walking over to the gate with Mrs. Thurston.

"Don't think she'll come up the valley, Mary. She's going home by Ingles. Tom will probably meet her."

He was right. They saw her shake hands with Mrs. Morton and then walk off down the lane without looking back.

"Come down now, Mary. We don't need a guard any more, and we've got to get ready for Tom."

Although there had been no sign of Macbeth, Mary recovered her spirits and went out to meet Dickie. When they had finally tidied up, put the potatoes in the embers and tied Sally to the lone pine, David led them out towards the wood. The twins were Red Indians again, and were talking to each other in secret "gabble language". The shadows were lengthening and David hoped that Tom would not be late because he had promised to be home for supper, and Peter had a long way to ride. He found the thicket and the tree to which the end of the guiding string was tied easily enough, and then gave his orders. The twins were to hide a little way off to come along behind Tom when he had passed them. Then he helped Peter up into the tree so that she could drop on her victim while he hid behind the trunk. They were hardly in their positions before they heard Tom's melodious whistling at the edge of the wood. He was making no attempt to be quiet, and they actually heard him laugh when he found the silver birch and the end of the string. Peter was certain that if he only stopped still for a minute he would be able to hear her heart thumping, but he came blundering on through the gloom of the wood. Then the twins spoiled David's plan - Tom had passed their hiding-place quite unsuspecting and in another minute would have been at the ambush tree. Peter could actually see him as he came towards them with his lips pursed in a silent whistle and a frown on his freckled face. He was looking as if he was getting tired of a rather silly game when the twins gave two blood-curdling war whoops, jumped out of their hiding-place and flung themselves at him.