Lowell, Massachusetts, February 1834

Mrs. Gird is still asking me to spy on the girls for her. I don't want to do it....I don't think I can refuse to try.

Grandmamma has died and Zellie has no other family. She desperately needs her job with mean-spirited Mrs. Gird, who runs a boardinghouse for the girls who work at the textile mills. When Mrs. Gird tells Zellie to eavesdrop and report what she hears, Zellie is surprised. The girls' conversations seem ordinary to her.

Then Zellie finds a puzzling list in one of the girls' rooms. A hidden note and whispers in the dark add to the mystery, until a budding friendship leads Zellie to a secret meeting where things become clear. She doesn't want to betray the girls, but if she doesn't, she could find herself jobless and homeless. Will Zellie risk everything to stand up for what she believes?