"I'll get the cow," Nancy offered, and went off toward the pasture to drive Primrose in. But the cow was not there. Nancy walked around the fence surrounding the field to see if there was any opening through which the animal might have wandered. Finally she found one, and saw hoof prints leading toward a patch of woods.

Nancy dashed off among the trees. She had never been that way before, but there was only one path to follow. Several times she paused to listen and thought she heard the faint tinkling of a cowbell somewhere ahead of her. It was rapidly growing dusky in the woods and Nancy hurried on. Again she stopped to listen. She could hear the cowbell distinctly now.

Primrose can't be far ahead," she thought in relief, and went in that direction. Nancy finally caught sight of the Jersey contentedly munching grass on the hillside beyond. Nancy stopped short and gave a gasp of astonishment-the sound of the cowbell had brought her to the mouth of the cave!

"I can hardly believe it!" she almost exclaimed aloud. This must be the other opening near the nature camp Jo told me about!"

Eagerly Nancy rushed toward the cave. But no sooner had she peered into the dark entrance than she was startled by the crackling of a twig behind her. Nancy wheeled to find a man standing not three feet away from her!

He seemed to have risen from the bushes which half hid the opening of the cave. Instantly it flashed through Nancy's mind that he had been stationed there to see that intruders did not enter.

"What're you doing here?" he asked, his voice as cold as steel.

Nancy recoiled. The man stood in the shadows of the shrubbery so that she could not see his face distinctly. But at the sound of his voice she knew instantly she was in danger.

"I must persuade him I wasn't spying," she thought desperately.