Based on Robert C. O'Brien's sci-fi novel from 1974, Z for Zachariah follows the life of Ann Burden (Margot Robbie) in the wake of a nuclear apocalypse that has devastated life on earth. In her mysterious countryside dwelling, crops continue to grow and she has built a sustainable, albeit lonely, lifestyle. Her new reality is disturbed when a mysterious, radiation-suit-clad scientist (Chiwetel Ejiofor) stumbles upon her peaceful property. Believing she was the only person left on earth, Ann is hesitant to welcome him in, but the two eventual begin an intimate relationship. Their newfound life together is challenged with the appearance of another man, Caleb (Chris Pine), creating a deadly love triangle in this post-apocalyptic tale of human relationship.