Resistance is set during World War II in Nazi-occupied Poland; the book spans roughly four years, from the German blitzkrieg in Warsaw on September 1, 1939, to the Warsaw Ghetto Uprising, which takes place in April 1943. The novel focuses on the Jewish resistance in Poland during this time, and specifically on three aspects of it. Firstly, it offers a glimpse into the roles women and children played in the resistance, particularly in their work as couriers. The courier system saw women and young girls disguise themselves as non-Jews to smuggle information, food, supplies, and even weapons into the Nazi-created ghettos of Poland, which were effectively sealed off from the rest of the world. The couriers continually risked their lives to carry out their work and even helped smuggle Jews out of the ghettos on occasion. The work of the couriers in the Jewish resistance movement often goes unrecognized, overshadowed by more militant forms of resistance, and Nielsen attempts to shed light on their significance.

Nielsen also highlights the different branches of Jewish resistance movements that persisted throughout WWII; the book specifically names Akiva and the ZOB, as well as actual historical figures associated with these movements. Akiva was responsible for “one of the first open acts of armed resistance by the Jewish people in occupied Europe” (317).