"You're not a boy, are you?" said Richard.

She laughed. "Everyone I know calls me Peter. I hope you will, too. My full name is Petronella Sterling... But we must go now or we'll never get home and Father'll be mad with me. There'll also be no time left for our exploring this afternoon"... and she heaved the haversack on to the pony's back and led the way along the top of the ridge. As far as they could see there was nothing but rolling hills and little gutters all looking exactly alike. With a shock David realized how easy it would be to get lost. Although the sun was shining brightly now, and it was difficult enough to know which way to go, it was rather frightening to imagine what would have happened if they had been up here without Peter, or in the dark or bad weather.

They were climbing now in single file. Peter, in front with Sally, was chattering over her shoulder about what fun they would all have together and asking whether they could swim. They reached the top of another ridge.

"Now we're nearly home," she said. "Look. There's Hatchholt and our bathing pool."

They panted up beside her and David whistled in surprise. They were looking down into a deeper and wilder valley than Dark Hollow. To their left was the gleam of water, and with a thrill he realized that they had found the hidden reservoir. The top end of the valley was a lake held in check by a dam which stretched from side to side below them. On the opposite side of the valley, built snugly into the hillside, was a trim little house. They could just see someone moving about in the garden and Peter suddenly put her fingers to her mouth and whistled shrilly. Sally, browsing in the heather nearby, pricked up her ears and stood stock still.

"That's my father," said Peter. "Let's wave to him so that he's not too surprised when we all come down." They all waved but as Mr. Sterling gave no sign that he had seen them, they started off down the zig-zag path.

Peter, who was leading Sally, suddenly stopped. "Would you like to ride down, Dickie?" she asked. The twins both looked so interested at this suggestion that David said quickly: "No. Not both of you at the same time. Dickie first, if Peter doesn't mind."

So Dickie was helped on and for a moment it seemed as if Sally was going to protest, but Peter took the bridle and spoke to her firmly and they set off down the hill again.

"I'm Red Wolf the Indian Chief," said Dickie.

"And I'm Tiger Lily his beautiful princess," said Mary.

"And we're trailin' the long trail over the prairie..."

"On the track of the pale-faces..."

And so they came into the valley. David looked puzzled.

"Where's the stream, Peter? There's no water down here."