At the center of the project and the book is the idea of the power of the individual to effect real change. This theme manifests itself in several ways, through several different characters. Most notably, of course, this theme is developed through the character of Irena Sendler. Irena was taught from a very young age that she must always help those in need, even if it means she may, herself, end up hurt. As a result, throughout her life, she is quick to step in to assist if it means helping someone else: a Jewish schoolgirl being attacked by other girls, for instance, or through her small act of resistance insisting on sitting on the Jewish side of the classroom at university, which gets her suspended indefinitely. This all eventually leads up to her biggest act of resistance—spearheading the project to save as many children as possible from the clutches of the Nazis throughout the war. Irena may be just one person, but through conscientious resistance and action, she nevertheless effected change.

However, this is seen through other characters, as well. Although the project eventually became a trio of students, it was started by a single student, Liz, who saw something in the story of Irena Sendler and chose to chase that lead.