Roller Skates opens with the narrator remembering back to a special year in the 1890s, when young Lucinda Wyman arrives at the Misses Peters' home in New York City; the two ladies will care for her during the year of Lucinda's parents' trip to Italy. The narrator's diaries help her remember the details of 10-year-old Lucinda's "orphanage," as she calls it. Miss Peters, a teacher, is "a person of great understanding, no nonsense, and no interference." Miss Nettie is shy and soft-hearted. Living with them Lucinda experiences unprecedented freedom, exploring the city on roller skates and making friends with all types of people.
Lucinda quickly gets to know Mr. Gilligan the hansom cab driver and Patrolman M'Gonegal. The first friend of her own age is Tony Coppino, son of an Italian fruit stand owner. Lucinda enlists Officer M'Gonegal to stop the bullies who knock down Tony's father's fruit-stand and steal the fruit. In return Tony takes her for a city picnic where they meet a rag-and-bone man. Later Lucinda reads Shakespeare with her favorite uncle and is inspired to put on a puppet production of The Tempest .
But the cold and snow of winter keep her cooped up indoors, and eventually a restless Lucinda acts out—and gets sent home from school in disgrace. Later her uncle introduces her to Shakespeare's tragedies, and she experiences her own when two of her friends die. With Lucinda's parents coming back from Italy she realizes everything is changing. So she skates to the park one last time. "How would you like to stay always ten?" she muses. "That's what I'd call a perfectly elegant idea!"