Set in 1904, Samantha Parkington [AnnaSophia Robb] lives in a spacious country house in Mount Bedford, New York, with her grandmother, Grandmary Edwards [Mia Farrow]. When Nellie O'Malley [Kelsey Lewis] and her sisters Bridget and Jenny [Olivia Ballantyne], along with their Irish immigrant father, arrive in town to work as servants at Samantha’s neighbor Eddie Ryland’s house, Samantha defends them from his bullying and they quickly become friends.
As their bond grows, Nellie reveals her mother’s death and that she has come from New York City after working in a factory with other immigrant children. Samantha offers to teach Nellie to read, and she also shares with Nellie about her own parents’ deaths in a boat accident. The two girls find comfort in their growing trust, and Samantha’s kindness shines as a beacon of hope for Nellie’s difficult world.
Samantha’s Uncle Gard [Jordan Bridges] arrives at Mount Bedford with his fiancée Cornelia Pitt [Rebecca Mader], and Samantha at first dislikes the pair because she fears further changes to her familiar life. Gard reveals their plan to marry in Mount Bedford at the end of July, and Samantha reluctantly agrees to be Cornelia’s bridesmaid. Although she worries Gard might forget her after the wedding, he reassures her that she will always be part of his family.
One night, Samantha overhears Gard talking to Grandmary about Samantha staying in New York City for the fall with Gard and Cornelia to make up for missing their trip to the St. Louis exposition. Upset, Samantha and Nellie hide in the boathouse overnight, a hiding place Samantha has made for herself. Eddie catches them the next morning and snitches on them; Samantha takes the blame but both girls are forgiven.
Samantha moves to New York City and regularly writes Nellie letters, sending her slides of the city for a stereopticon, a gift from Uncle Gard that Samantha had given Nellie. At her new school, Samantha and the other girls are instructed to write a speech about “Progress in America” for a Christmas program in front of the entire school, and Samantha chooses to write about factories.
A letter arrives from Grandmary’s maid saying that Nellie’s father has died from influenza and that the girls have been sent to an orphanage in New York City. Samantha and Cornelia visit the orphanage thanks to donations from Cornelia’s friends. They discover a poorly run, thieving matron and that Nellie has been separated from her sisters. Samantha helps the three girls escape and hides them in Gard and Cornelia’s attic while Nellie goes back to work at a factory.
One morning, Bridget wakes with a fever, so Samantha goes to the factory to find Nellie and witnesses the harsh realities of child labor. Nellie leaves to care for Bridget, and Samantha confesses to her aunt and uncle about hiding the girls in the attic. They allow them to stay for the moment, but Gard says he must involve the authorities. Moved by the abuses she witnessed, Samantha rewrites her Christmas speech to argue that America cannot claim progress or pride in its factories until conditions improve.
In the winter, near the end of Samantha’s original stay, Cornelia and Gard ask her to stay in New York City permanently after Grandmary finally accepts Admiral Bemmis’s proposal, which Samantha also accepts. She asks if Nellie, Bridget, and Jenny can stay with them to work as maids, and the trio reveal on Christmas morning that they will not only stay but be adopted along with Samantha. They all accept, with Jenny uttering her first words since the passing of her mother. The film closes with Samantha gifting presents to the girls living in the orphanage under a new owner, marking a hopeful new chapter for everyone involved.
