Z for Zachariah is a novel by Robert C. O'Brien which was published posthumously in 1975. It is written from the first person perspective of a sixteen-year-old girl named Ann Burden, who survives a nuclear war in a small American town. The town's location is in a geographically distinct and remote valley that shelters it from the nuclear fallout. The book takes the form of a diary kept by Ann as she recounts the events that followed the war.
Z for Zachariah won an Edgar Award in the juvenile category in 1976. The book's title is explained by the main character. Recalling that Adam, whose name begins with the first letter of the alphabet, was the first man according to a Bible-themed children's alphabet book, she presumes Zachariah is the Bible's last person, as he is the last person named in the book.
When he is a little better, the man introduces himself as John Loomis, a (plastics) scientist who helped design the radiation-resistant material used to make the suit and cart cover. He was in his underground lab when the war began, and after the contamination, ventured out in the suit with supplies in his cart to try and find survivors, and he came across the valley. When Ann asks him who Edward was, however, he refuses to talk about it. The radiation sickness soon overtakes him and he falls into a [coma], during which Ann takes care of him. He sometimes talks in his sleep, however, and during one of his dreams in which he does such, Ann learns that Edward was a lab colleague of his who wanted to take the suit to go and search for his family. John didn't want this, as he wasn't sure if he would bring the suit back, and they had a fight in which John murdered Edward. Nevertheless, Ann continues to take care of the man of greenish plastic.
When he recovers, things are well for a while and they make plans on how they will cultivate the valley and survive onward. But soon, John starts to act funny. He watches Ann possessively while she plays the piano, and she becomes nervous. Then, one night, he comes into her room thinking she is asleep and attempts to rape her. Ann escapes and is forced to flee. For several months the two play cat-and-mouse around the valley, with John ruthlessly trying to find Ann by using her family's dog, Faro, which also survived, to track her. John locks all the food and farming equipment in the barn, forcing Ann to come back or starve, and burns her possessions from the cave in which she was hiding. In her plan to escape, she takes Faro into the contaminated water and he dies the next night.
Ann wishes for them to coexist in the valley, but one day, when she approaches the house to speak with him, he shoots her in the ankle (presumably to cripple her so he can imprison her) and she realizes she must leave the valley. She steals the protection suit and the cart, but decides to talk with John one last time before she leaves. He attempts to kill her, but Ann tells him that if he did then it would be like what he did to Edward and he would truly be alone, and he instead points her in the direction out of the valley where he had seen birds circling; thus offering hope both that the world has not been totally destroyed and that his character is redeemable. The book covers a number of themes including loneliness, isolation and loss, as well as attempted murder.
A television adaptation of Z for Zachariah was shown as part of the BBC's Play for Today season in 1984 starring Anthony Andrews and Pippa Hinchley. This version was set in a Welsh valley. Many people hold this sole adaptation of the story in very high regard, which may be the reason it has not yet been adapted for a feature film.
Rumours of a film adaptation of the story have been circulating the internet, but are not confirmed.