Samantha and her family are spending the summer at Piney Point, Grandmary's home in the mountains. One day Samantha and the twins, Agnes and Agatha, find a sketchbook made by Samantha's mother. In it, Samantha sees a beautiful waterfall she had visited with her parents long ago, before they died in a boating accident. Using the sketchbook as a map, Samantha and the twins set off. When their secret exploration puts them in the middle of a dangerous storm, Samantha must save the day.
