Only once had there threatened to be any trouble between the chums on account of rivalry over the cars. That had been when Mollie had taken Betty's "dare" to a race and Betty's little roadster had won the day, racing like a streak of light along the country road and leaving Mollie's high-powered but more clumsy car far behind. But Mollie had taken her defeat like the little sport she was--even though it must be admitted she had been considerably disappointed and taken aback by her failure--and in her ever since there had been a great respect for Betty's car. But now she eyed with impatience the bent figure of the Little Captain as she still leaned over the wheel, her ear tuned to the purr of the engine. "For goodness' sake, what's the matter with you?" she cried. "I thought you were the one who was in a hurry to be off and now look at you--sitting there like--" "Engine is missing," Betty informed her briskly. "Guess I had better have a look--" "If you start fussing with bolts and screws now, you can count me out," said Mollie, resolutely climbing back into her car. "It is ten o'clock already, and we won't be home before night if we don't hurry." "Oh, all right," laughed Betty. "But if the car gives out before we get back don't blame me, that's all." "It would give me the greatest of pleasure," said Mollie with a diabolical chuckle as her machine moved off down the street, "to have everyone in Deepdale see me towing your poor little flivver through the town." "Huh," sang back Betty scornfully as the roadster responded eagerly to her touch, "they will have a great deal better chance of seeing me in the lead with your great big jumbo tottering feebly at the end of a rope." They picked up Amy and Grace on the way and were soon flying swiftly down the road in the direction of Professor Dempsey's tree-surrounded home. They were in rather good spirits at first, for now that they were really on the way to doing something, though they were not quite sure what, they felt relieved and almost gay. But as the distance shortened between them and their destination, a strange depression that they could neither explain nor brush away settled down over them. Once, Grace, who sat beside the Little Captain in the roadster, sighed rather dolefully and Betty looked at her out of the corner of her eye. "Do you feel that way too, Grade?" the latter asked. "What way?" asked Grace uncertainly. "That sigh, do you mean?" "Yes," nodded Betty. "You sounded rather mournful and that is exactly the way I feel. What's the matter with us, anyway? Where are our spirits?" "I suppose we couldn't expect to feel joyful," said Grace after a little pause. "We aren't going, so far as I can see, on a very happy errand, you know." "But I don't think it is that alone," said Betty, with a shake of her head. "I feel as if we were going to see something perfectly dreadful--"