In 1942, a young social work­er named Ire­na Sendler was grant­ed access to the War­saw Ghet­to as a pub­lic health spe­cial­ist. While there, she began to under­stand the fate that await­ed the Jew­ish fam­i­lies who were unable to leave. Soon she reached out to the trapped fam­i­lies, going from door to door and ask­ing them to trust her with their young chil­dren. She start­ed smug­gling chil­dren out of the walled dis­trict, con­vinc­ing her friends and neigh­bors to hide them. Dri­ven to extreme mea­sures and aid­ed by a net­work of local trades­men, ghet­to res­i­dents, and a lover in the Jew­ish resis­tance, Ire­na made dan­ger­ous trips through the city’s sew­ers, hid chil­dren in coffins, snuck them under over­coats at check­points, and slipped them through secret pas­sages in aban­doned build­ings, keep­ing the names of the thou­sands of chil­dren she saved in a secret list buried in bot­tles under an old apple tree in a friend’s back gar­den so that their fam­i­lies could find them after the war. She could not know that more than nine­ty per­cent of their fam­i­lies would perish.