Penny had no immediate answer to this, and Jon looked at her in surprise. Her chin was up and her grey eyes gazed across the levels to the sea. The wind whipped her hair back from her face which, for once, was very serious.

She climbed another fence and sat on the top rail before she said quietly, "I know we ought not to risk anything if it means losing the treasure, but you said yourself that we were a step ahead of the Ballinger gang - I've just thought of that name for them. I think we're quite clever enough to deal with the old woman, and Slinky, too, if we go on pretending to know nothing. There isn't really anything they can do as far as I can see... And besides, Jon, I've made up my mind that we've got to do this without grown-ups. It might make it easier if there were more of us, because I think we ought to be watching Slinky and Miss B. all the time. It's by watching them that we might find out a lot."

Jon looked at her in admiration.

"You mean we might drop them an innocent hint and let them do some of the thinking for us?"

Penny nodded brightly, although she had not really thought as far ahead as that!

"We're nearly there now," Jon went on. "But I'll tell you what we'll try and do presently - when we've had our sandwiches perhaps. We'll go through everything we've discovered so far - I'll write it down if I've got my note-book - and we'll talk it over sensibly and see if we get any nearer that way."

They were close enough now to see that the castle walls, viewed from the outside, were still in fairly good condition and that the building itself was very much bigger than they had imagined. The round, squat central keep did not rise very high above the outer walls, but what struck them most forcibly was the castle's loneliness.

They stood for a moment in the big, grassy space inside the crumbling walls. The sun beat down upon them, and they were sheltered, too, from the breeze. The only sounds were the monotonous baaing of the sheep and the ceaseless song of the larks overhead.

"I wouldn't like to be here at night," Penny said at last. "I wouldn't like it at all. It's all right now with the sun-shine, but I wouldn't like it at night."