Samantha is determined to help nine-year-old Nellie, attending school for the first time, with her school work and learns a great deal herself about what it is like to be a poor child and work in a factory.
When Samantha's tenth birthday party is spoiled by the boy next door, Aunt Cornelia and her young twin sisters try to ease Samantha's disappointment by inviting her and Grandmary to visit them in New York City.
While spending the summer at Grandmary's summer home on Goose Lake, Samantha and her twin cousins decide to visit the island where Samantha's parents were drowned during a storm.
When she discovers that Nellie and her sisters have been sent to an orphanage, Samantha, now living with her aunt and uncle in New York City, tries to help her friends as much as she can.