The novel begins in Ireland in 1896. A child, Willie Dunne, was born as a thunderstorm occurs outside the Rotunda maternity hospital in Dublin city centre. Willie was brought up with love by both his mother and father; but his mother died in childbirth when Willie was twelve, and Willie was then brought up by his father and three sisters. As he grew up, Willie deeply felt his loss. Moreover, his father’s hopes, that Willie will follow in his footsteps and become a policeman are unfulfilled because of Willie’s small physical size. Willie felt his insufficiency deeply. The narrative leaps forward to early 1914, when Willie was just short of seventeen years old and became a fairly happy trainee builder. Willie ran errands for his father to take offerings of food to Mr Lawlor, a neighbour living in a slum apartment nearby. There he met Gretta Lawlor, a thirteen year old girl with whom he fell in love with. Mr Lawlor, a transporter and walker on behalf of trades’ union recognition, was injured in street fighting attending the Dublin lockout of 1913, beaten by Dublin Metropolitan Policemen under James Dunne’s command. 
Like many of the Dublin poor forcibly dismissed after the lockout, Mr Lawlor joined the British Army. His duties mean he was often away from home. Willie’s visits as the year progressed led to a growing intimacy and love. The young couple’s relationship remained a secret to their fathers, but despite Lawlor’s poverty, Willie was confident that he can gain his father’s permission to marry. At the outbreak of the war in August, Willie told Gretta that he was going to join the British Army just to satisfy his father. Gretta was unhappy and did not want him to go, but Willie reminded her of his father’s opinion that a man should act according to his own thoughts and beliefs. The chapter closes as Gretta disclosed that, unluckily, these opinions were taken from the Christian philosopher, St Thomas Aquinas.

Paul described his fellow soldiers: he, Leer, Müller, and Kropp were all nineteen years old. They were from the same class in school, and each registered in the army willingly. After a sound night’s sleep, the men lined up for breakfast. The cook had innocently made enough food for 150 men. The men were nervous to eat the foods entitled to their fallen comrades, but the cook insisted that he was only allowed to distribute single food and that the dead soldiers’ food will simply have to go to waste. After a heated argument, however, he agreed to distribute all of the food. Paul remembered that he and his friends were embarrassed to use the general latrines when they were trainees. Now they found them a luxury. Every soldier was intimately acquainted with his stomach and intestines. The men settled down to rest, smoke, and play cards in order to forget about their narrow survival during their last trip to the front. Kemmerich, one of Paul’s classmates and a member of the Second Company, was in the hospital with a thigh wound.
Paul recalled his schoolmaster, Kantorek, a violently nationalistic man who persuaded many of Paul’s friends to enlist as volunteers to prove their loyalty. Joseph Behm, was hesitant but eventually gave in to Kantorek’s merciless pressure. He was one of the first to die, and his death was particularly horrible. With Behm’s death, Paul and his classmates lost their innocent trust in authority figures such as Kantorek. Kantorek wrote a letter to them filled with the empty phrases of patriotic feeling, called them “Iron Youth” and glorifying their heroism. The men reflected that they once idolized Kantorek but now despised him; they blame him for pushing them into the army and exposing them to the horror of war.

Paul reflected that he and the other young men of his generation were cut off from life just as they had begun to live it. The older soldiers had jobs and families to which they can return after the war, but the younger men had nothing; the war had become their entire lives. Whereas the older men forgot the ditches and the death, the young men had nothing positive on which to focus thoughts of the future. Their pre-war lives were unclear, unreal dreams with no relevance to the world that had been created by the war. Paul felt utterly cut off from humanity; his only feelings of love and loyalty were those that he shared with his friends and fellow soldiers. As a result, Paul tried to see them in the best possible light. He thought about Müller’s attempt to persuade the dying Kemmerich to give him his boots and tried to convince himself that Müller was being reasonable rather than selfish. During training, Paul and his classmates were taught that patriotism requires suppressing individuality and personality, a sacrifice that civilians do not require of even the lowest class of servants. Corporal Himmelstoss, formerly a postman, trained Paul’s platoon. He was a small, petty man who relentlessly humiliated his recruits, especially Paul, Tjaden, Haie, and Kropp. 

Eventually, Paul and the others learned to stand up to Himmelstoss’s authority without outright defiance. Paul and his friends detested Himmelstoss, but now Paul knows that the humiliation and the arbitrary discipline toughened them and probably helped them to survive as long as they have. He believes that had Himmelstoss not hardened the men, their experiences on the front lines would have driven them insane.
Kemmerich is very near death. He is saddened by the fact that he will never become a head forester, as he had hoped. Paul attends Kemmerich’s death throes. He lies next to his friend to try to comfort him, assuring him that he will get well and return home. Kemmerich knows that his leg is gone, and Paul tries to cheer him with talk about the advances in the construction of artificial limbs. Kemmerich tells Paul to give his boots to Müller. Kemmerich begins to cry silently and refuses to respond to Paul’s attempts at conversation. Paul goes to find the doctor, who refuses to come. When Paul returns to Kemmerich’s bedside, Kemmerich is already dead. His body is immediately taken from the bed to clear room for another wounded soldier. Paul takes Kemmerich’s boots to Müller.