The Peppers - Mrs. Pepper and her five children Polly, Ben, Joey, Davie and Phronsie - are a poor family (the six of them sleep in a total of four beds in two rooms), but they love each other and as a result are happy. Mrs. Pepper's husband, John Pepper, a mining engineer, died when the copper mine in which he had half ownership collapsed atop him. Mid-teen Polly was deeded his part of the mine, which her mother has told her her father wanted her to keep at least until she became of age, despite he never having found copper in it. Polly often acts as the family guardian to her siblings while Mrs. Pepper is at work. By chance, Polly and Joey meet well-off but lonely mid-teen Jasper King, who ends up befriending all the Pepper children. Jasper lives with his wealthy businessman grandfather, J.H. King, who pays his grandson no attention as he is all consumed with making money to the exclusion of all else. J.H.