Mr. Cameron has purchased a winter camp deep in the wilderness near Scarboro, New York. Helen and Tom have received permission to take Ruth and their other friends to Snow Camp for the latter part of their winter break. Before the friends depart, they cross paths with a strange, sullen boy named Fred Hatfield, who comes from Scarboro. Mr. Cameron has a suspicion that the boy is a runaway and decides to take him back to his family in Scarboro.

The Cameron party departs for Snow Camp with Fred Hatfield as an unwilling passenger. On a brief stop near Scarboro, Fred jumps off the train, and Ruth impulsively follows. Fred steals a wagon which is parked in front of a store, and Ruth jumps on board. What follows is a harrowing adventure in which the two are nearly attacked by a panther and are later rescued by a crazy hermit.

The hermit takes the two young people to Snow Camp, but Fred disappears just before they arrive. As fate would have it, Ruth encounters Fred Hatfield several more times during their stay at Snow Camp. In the end, Fred is reunited with his family, and Ruth and her friends return from an enjoyable vacation.