Lois Lowry's "Number the Stars" follows Annemarie Johansen, a young girl growing up in Nazi-occupied Copenhagen during World War II. Through Annemarie, the novel explores the growing power of the Nazi party and the efforts of the resistance movement in Copenhagen.
"Number the Stars" begins with Nazi soldiers stopping Annemarie and her friend Ellen Rosen on their way home from school. The two girls and their families soon discover that the Nazis have closed a local Jewish-owned shop. Annemarie learns more about the resistance movement from Peter Neilsen, a family friend who was engaged to Annemarie's sister, who died before the events of the novel.
Ellen's family is forced to flee, leaving their daughter with Annemarie's family. Ellen pretends to be Annemarie's sister, keeping her safe from Nazi soldiers who come to the house to investigate. Soon, Annemarie's uncle Henrik prepares to smuggle the Rosens and several other refugees to Sweden to escape the Nazis. Annemarie is given a package to deliver to Henrik's boat, but she is stopped by soldiers on the way. The package contains a handkerchief, which Henrik tells her is to throw Nazi dogs off the scent of the refugees.
The novel ends with the end of World War II, when Annemarie learns that her sister died because she was a member of the resistance movement.