Louisa May Alcott is 15 years old during the time this tale takes place. Her mother has gone to New Hampshire to work, as the perpetually impoverished Alcott family has no source of income (their father, Bronson Alcott, refuses to work for another person). As they are active on the Underground Railroad, it falls to Louisa to help escaped slave George when he arrives at the Alcott house and Bronson is in no condition to assist.
The book also deals with the Alcott family's friendships with Ralph Waldo Emerson and Henry David Thoreau, and the Transcendentalist movement -- as well as politics and issues related to slavery. All the same, the book would be readily comprehensible by the so-called "young adult" readers. It was an okay, quick read ... but not a particularly challenging story.