The context in which the story is set, Z for Zachariah is in a lonely valley, where Ann Burden, the only survivor of the nuclear holocaust encounters Mr Loomis, a shadowy and mysterious stranger.
Her family and surviving residents leave the valley in search of other possible survivors. There were none and when they next leave the valley they never returned. This can be seen when Ann's father says " Terrible, terrible.We drove around , looking.We blew the horn. Then we went to the church to ring the bell. You can hear it five miles away.We waited for two hours, but nobody came.I went into a couple of houses-The Johnson's, The Peter's -They were all in there, all dead."
Mr. Loomis having traveled from Ithaca, New York has gone through every village he has seen to only find dead corpses. This is proved when Ann writes in her diary saying “It has taken him ten weeks to get from Ithaca to the valley, and all that way, all that time, he had seen no living thing, no people, no animals, no trees, not even insects—only grey waste
land, empty highways, and dead cities and towns.” He had little hope in finding survivors until he saw the valley where he meets Ann Burden. During the events with Mr. Loomis, Ann faced dangers due to Mr. Loomis having mood swings from nuclear sickness and the killing of Edward. This happened when Mr. Loomis held Ann’s hand in a possessive way and when he sneaks up on Ann. This is said in Ann’s Diary “ There was nothing gentle about the way he held my hand and no expression at all in his face. He just looked at me as he had at The Farm Mechanic" (pg120)
That is the context of Z for Zachariah in which the story is set which is the only valley with possibly the only surv
ivors left after the nuclear holocaust.