Uncle Reuben comes to visit, bringing his seventeen-year-old granddaughter, Ruth, with him. She seems very shy, and John kindly tries to make her feel at home. Unfortunately, this is misinterpreted by Ruth, mostly because John's mother is trying to play matchmaker. Ruth will inherit all Reuben's wealth, and Mrs. Ridd thinks she would be an excellent wife for John. Meanwhile, Uncle Ben is acting very strangely. He goes out every day on horseback, stays for long hours, and comes back mudspattered and weary, yet not telling anyone what he's been up to. Annie, Lizzie, and Ruth, are very curious and convince the hired man, John Frye, to follow him. He trails him to a remote and dangerous section of the moor, where there is a terrible sinking hole which will suck in anyone caught in it. He loses Reuben and gets frightened away, so the girls and John are still in the dark as to what Reuben is up to.
Deeply concerned, John arranges to have her maid Gwenny put up a signal where he can see it from the farm if she is in trouble and needs him.