One of the themes that come out of the novel is the internal and external conflicts, with the former being that which exists within the individual — that is, individual versus self; while the latter is related to the conflicts relating to people and the environment.

For internal conflicts, we see several examples in Ann’s life. She struggles to convince herself to do good to Mr. Loomis even though he does not appreciate her efforts, especially after his recovery from the illness. He mistreats her, shoots at her, and even attempts to rape her on more than one occasion. Ann is torn between helping Mr. Loomis and leaving him alone to fend for himself. Being the introspective individual, she fights her negative thoughts of Mr. Loomis by going to church and praying for him.

“It is different when there is no one else present, no one to turn to or tell about it. And I found myself doing what I have long since banned myself from doing—that is, imagining my parents were coming back, with David and Joseph, and wishing they were. I put the thought out of my head, as I have learned to do. I felt somewhat calmer then, and was able to continue with the dinner…” (O’Brien, 1975). 

The external conflict relates to the people and the world around them. Since the nuclear attack where virtually all people seemed to have been wiped out, the surrounding regions have been left desolate and harmful to the effects of radiation. Ann cannot go to town; she cannot jump into Burden Creek for a swim, or even drink from the water. We see the repercussions when Mr. Loomis unknowingly exposes himself to the harmful water, becomes very sick, and ends up on the verge of death. Over time, the external conflict develops between Ann and Mr. Loomis, especially after his recovery, where his change of character causes a strain in their relationship. He attempts to assault Ann Burdens sexually when she declines his advancements; he blocks her from accessing the store for food and other essentials, and he even chases after her driving the tractor and shoots at her several times. The strained relations reach a climax when Ann steals the safety suit and leaves the valley as she no longer able to bear the mistreatment, and sets off to find a more habitable place. 

“I have no choice,” I said. “I didn't want to die, and you wouldn't give me anything. During the winter I would have starved on the hillside. I don't want to live with you hunting me as if I were an animal, and I will never agree to be your prisoner.” I felt reassured by my voice and talked on: “I’ll search for a place where there are other people, people who will welcome me. To stop me you will have to kill me, too.” (O’Brien, 1975).

Another major theme in the book is one of survival, which we get to see through the life of the protagonist, Ann Burden. Just at the tender age of 15, she is forced to fend for herself after her family and neighbors disappear. She is forced to take care of the farm, the crops and the animals, which are the source of food in the isolated village where she has lived alone for a year before encountering John Loomis, the only other human being in existence. Her life situation deteriorates when she is betrayed by Mr. Loomis, where he pushes her out of her home forcing her to spend the winter in a cave with little to survive on. We get a glimpse of how hard things are based on her description of the desolate landscape, from her vantage point at the top of Burden Hill. She states, “I have climbed the hills on all sides of this valley, and at the top, I have climbed a tree. When I look beyond, I see that all the trees are dead, and there is never a sign of anything moving…” (O’Brien, 1975).

While Mr. Loomis was recuperating from the sickness resulting from the radiation exposure, Ann serves him breakfast. We get the glimpse of the solitary life that she had to go through, and how she tried her best to survive in such desolation from the response of Mr. Loomis; even he was surprised at her abilities, “Amazing,” he remarked, when she brought him the very first breakfast tray. “This. Fresh eggs. Toast. Coffee. This valley. You, all by yourself. You are all by yourself?” (O’Brien, 1975). Additionally, the author’s use of a personal diary format and the use of the first person in writing accentuates the theme of survival; the reader is given a chance to get into Ann’s mind to view and experience her challenges. The reader can almost vividly share her feelings of solitude, desolation, and emptiness.

Dystopia, a word that is synonymous with extreme chaos and misery, was another important theme found throughout the novel. The human-caused suffering, a product of war, has left the land barren, a danger to the only survivors who must venture outside the small village with great precaution or risk being exposed to the radioactive environment that could kill them. Throughout the novel, the author, through the words of the protagonist, paints a picture of how dire the situation is, where she talks about the unforgiving landscape that has taken away all life. The introduction of Mr. Loomis paints a picture of the desperation that the only two survivors are experiencing. He introduces conflict through how he treats Ann, pushing her to tend to the crops; he is a villain, a murderer and, in the end, a usurper of the land — the only oasis in an unforgiving landscape (Hall, 2007). Mr. Loomis’s dispossession, dishonesty, chicanery, and cunning ways propagate the dystopian theme. Despite being assisted in his recovery by Ann following the radiation exposure, he turns on her, disposes her of her home and land, and attempts to rape and potentially kill her (Hall, 2007). He introduces conflict, dishonesty, and hatred.

The author introduces the first character in Chapter One when Ann, the protagonist, states, “I am afraid. Someone is coming.” She goes into hiding and, before that, even covers up the garden and makes the whole place seem uninhabited. Mr. Loomis senses that the area is safe judging from the trees and the landscape that had signs of life, and he even calls out to ascertain if any people are living in the area. Despite his constant calls, Ann does not make her presence known until the time when she feels she could trust him, and that he needed her help. The often-complicated association between Ann and Mr. Loomis portrays the theme initially when she takes him in and aids in his recovery following exposure after swimming in a pool of radioactive water.

We get a feel for the teamwork from Ann’s words. She helps him recuperate from the exposure by providing medication, preparing meals, and tending to the garden and animals. “I had a lot to do,” she states, “With him in the valley—in the house—I decided I should cook better meals than I did when I was by myself...” (O’Brien, 1975). Throughout Chapters Seven thru Twelve, Ann is the one providing for Mr. Loomis, who is very sick and, on certain days, may even be too weak to do anything. “I am back in the house, in my room,” she exclaimed. “The man is in the tent. He is asleep, most of the time at least, and so sick he cannot get up. He scarcely knows I am here…” (O’Brien, 1975). Ann will have to compete against the stranger and act smart for her survival; she cannot put herself to trust him. 

Another critical theme in the book is one of faith and trust. We get a glimpse of the theme in the last chapter when Ann has given up after being thrown out of her home and living in the cave. She decides it is time to find a more habitable place, somewhere she will feel welcomed. Mr. Loomis tries, though unsuccessfully, to convince her to stay, “Don't go,” he said, “don't leave me. Don't leave me here alone…” Mr. Loomis has failed her; she has lost trust in him. In response to his request for her not to leave, Ann says, “You have the valley. There was bitterness in my voice. And suddenly, feeling near tears myself, “You didn't even thank me for taking care of you when you were sick.” So my last words were childish…” (O’Brien, 1975).  Their relationship has been somehow complicated and is filled with great distrust and misunderstanding. Mr. Loomis betrayed her trust by coming in and receiving help and subsequently turning on her. He even attempted to sexually and physically assault her on several occasions.

There is a glimmer of hope and restored faith when Mr. Loomis offers advice directing her to the west, “He was standing at the edge of the deadness. He was pointing to the west, and he seemed to shout the same thing over and over. “Birds,” he said. “I saw birds… west of here… circling…” (O’Brien, 1975). Ann sets off in faith, in that where she was directed, she would find some life. In the last paragraph of the book, we see the same theme of faith in her dreams, “While I was sleeping the dream came, and in the dream, I walked until I found the schoolroom and the children…” (O’Brien, 1975).