At age eleven, Rosie Lepidus's main concerns are winning ring-a-levio, going to school, and staying out of trouble. But when Mama falls ill with pneumonia and Papa throws all the family's savings into the nickelodeon business, the burden of caring for her family falls on Rosie's shoulders.

Tall for her age, Rosie is able to pass for sixteen and take Mama's place sewing sleeves at a shirtwaist factory. Her family needs the money. But working conditions are horrible and the factory boss is incredibly strict. The girls are fined for nearly everything -- even talking or humming! Within days of starting work, Rosie hears the buzz about a huge strike of twenty thousand shirtwaist workers. It's the strike that Mama's been working toward for ages: a huge push for change in the workplace. Rosie wants to join in, but as the streets become more dangerous, Papa asks his daughter to return to school. And Rosie must choose: follow Papa's orders...or fight with everything she's got.