Nat Blake, a young traveling musician whose father recently died, arrives at the Plumfield School for Boys. He has been sent by the matron Mrs. Jo’s brother-in-law, Uncle Teddy, who discovered Nat living in a damp basement, neglected by his guardian Nicolo because of illness. Uncle Teddy believes the boy is a talented violinist and hopes Mrs. Jo can help Nat regain his strength and earn a living from his music.

Nat is grateful for the hospitality and charmed by the people at Plumfield School. He meets some of the other students—Ted, Demi John, Daisy, George, and Rob. That night, Nat plays a beautiful tune on the fiddle for them, and they are all enthralled with his musicianship, and ask him to play more. Nat is overcome with emotion at their warm welcome.

Nat notices that the school is unusual and has few rules. The boys are allowed to play boisterously, slide down banisters, and have pillow fights on Saturdays. Mrs. Jo tells him that by giving the children the freedom to play and be happy, they will "learn how to help themselves and be useful men” (12).