"We are going back to the house now and get you something hot to eat," said Betty, as they rejoined Amy and Grace and started off toward home. "Afterwards if everybody's willing we will hunt this strange beast that jumps out from porches and leaps into rivers just for the fun of the thing. But just now, Billy Billette, you are going home." But Mollie had been more severely shocked than she was willing to admit by her experience, and it was some time before the girls visited the falls or the river again. Meanwhile they contented themselves with exploring the country about the lodge, taking short trips in the cars and wondering whether the boys would really be home before the summer was over. Their days were not altogether happy, however, for the thought of that weird thing prowling around in the woods and ready, for all they knew, to spring out at them at every turn, refused to be banished from their minds. Then, too, they thought a great deal about poor Professor Dempsey and the little ruined cottage in the woods. Somehow, they had an uneasy feeling that if they had gone to him at the very first minute they had heard of his trouble they might have helped him. Whereas, they had waited and--he had fled. For a while the idea of a dip in the swimming pool was naturally not very attractive to Mollie, but at last there came a day when she herself suggested it and the girls enthusiastically seconded the motion. More than the prospect of a good time, was the hope, unexpressed, that they might see again that strange thing which Amy and Mollie had only glimpsed the time before. Perhaps, they thought, if the mysterious thing were faced in the open and in broad daylight, it might prove to be no mystery at all but something ordinary and commonplace enough to do away with all their vague and weird imaginings. But in this expectation they were most completely disappointed. Nothing at all unusual occurred and although they enjoyed their swim in the warm back eddy of the pool, they came away disgruntled and with a curious feeling that they had been cheated out of something. "I only wish the boys would come," sighed Amy, as they turned in once more at the lodge. After that the "Thing" became almost like an obsession with them. They must find out definitely what it was that was spoiling all their fun. They began to haunt the river, especially at the foot of the falls, in the hope of seeing something, anything that would put an end to their curiosity and uneasiness. For a long time they had not got up courage enough to visit the place at night, but at last they became curious enough to brave even that. "We have simply got to find out something," Mollie whispered to Betty as on this particular night they stood on the porch and waited for Mrs. Irving to join them. "We can't go on this way any longer, Betty. Why, I am getting so nervous I jump if you look at me."