Across the now placidly flowing Lumano where it widened into almost the proportions of a lake just below the picturesque Red Mill, a bank of tempestuous clouds was shouldering into view above the sky line of the rugged and wooded hills. These slate-colored clouds, edged with pallid light, foredoomed the continuance of the peaceful summer afternoon. Not a breath of air stirred on the near side of the river. The huge old elms shading the Red Mill and the farmhouse connected with it belonging to Mr. Jabez Potter, the miller, were like painted trees, so still were they. The brooding heat of midday, however, had presaged the coming storm, and it had been prepared for at mill and farmhouse. The tempest was due soon. The backyard of the farmhouse-a beautiful lawn of short grass-sloped down to the river. On the bank and over the stream itself was set a summer-house of fair proportions, covered with vines-a cool and shady retreat on the very hottest day of midsummer. A big robin redbreast had been calling his raucous weather warning from the top of one of the trees near the house; but, with her back to the river and the coming storm, the girl in the pavilion gave little heed to this good-intentioned weather prophet. She did raise her eyes, however, at the querulous whistle of a striped creeper that was wriggling through the intertwined branches of the trumpet-vine in search of insects. Ruth Fielding was always interested in those busy, helpful little songsters.