It is the summer of 1955, and ten-year-old Toby and his mother, Rosemary are driving from Florida to Utah in their decrepit car. They are on their way to Utah to make their fortune by mining uranium ore, and to escape Roy, an abusive ex-husband of Rosemary's who she has taken up with again. The car overheats and they stop to let it cool. While Rosemary and Toby are waiting, they see a big truck careen over the road's guardrails and fall hundreds of feet into the river gorge below. For the remainder of the day, Rosemary dotes on Toby and he takes advantage of her sentimentality to buy Indian souvenirs. Toby and Rosemary have faith that their luck will change for the better once they arrive in Utah. Rosemary recalls how when she was a child, before the ##Stock Market Crash of 1929# she lived in a big house in Beverly Hills. Her father was a "paper millionaire," and Rosemary dreams of return to this comfortable lifestyle. When they arrive in Moab, Utah, however, Toby and his mother find that they are months too late. People just like them have swarmed the state's mining towns looking for fast money and a new life. This sudden influx of people has turned Moab into a dangerous slum. There are no jobs, and the Geiger counters necessary for mining are overpriced. Rosemary decides to buy a "poor man's Geiger counter"—a black light which supposedly makes uranium glow—and to drive to Salt Lake City, where she is confident she will find work.
Toby wishes to change himself, and vows not to be the same boy he was in Florida. Toby wants to change his name to Jack, after the author Jack London, and his mother begrudgingly concedes on the condition that Toby enroll in catechism classes and take Jonathan as his baptismal name. Toby's father, who is now married to a rich woman in Connecticut, does not want Toby to change his name or become a Catholic, and claims that Toby will be breaking with family tradition. This tradition, Toby later learns, is a lie. Toby feels that by shedding the name his father gave him he will shed any attachment to his father, who has never provided for Toby or his mother.
Toby, known as Jack for the remainder of the book, attends Catholic school, where he is taught by Sister James. In an effort to keep her students out of trouble, Sister James develops an after-school program. Jack joins the archery club. One day, as Jack is preparing to shoot at a classmate, Sister James catches him. Jack is very ashamed of himself, feeling deeply guilty and "unworthy," as he often does throughout the rest of the memoir. Jack feels such shame at being caught, he habitually skips archery and even some of his classes. His mother does not have a phone, so there is no direct way for her to find out.
When Jack isn't playing with his Mormon friends, he is roaming the streets, befriending dogs and strangers. He sees businessmen and imagines that each one is his father. Jack also uses his vivid imagination in his letters to Alice, a pen pal from Phoenix. In his letters, Jack glamorizes his life to be what he wants to live, and not what he's living. As he wanders around town, often Jack feels deeply lonely.
Roy has followed Jack and Rosemary to Salt Lake City, and spends most of his time at Rosemary's apartment. Every day, Roy sits in his car outside of Rosemary's office, waiting for her to leave work so that he can follow her home. Jack sometimes comes with Roy, although Roy makes Jack promise not to tell his mother. On one such trip, there is no sign of Rosemary. Roy drives wildly around the block, and when he and Jack return home to find Rosemary cooking dinner, Roy accuses her of having an affair. Rosemary explains that she had only left work early to go shopping. According to Catholic ritual, Jack must go to confession before he can receive communion. Despite his general feelings of guilt, Jack cannot bring himself to confess. To relax him, Sister James gives Jack cookies and milk, and tells him that as a child, she was a "backbiter" and a thief. When Jack reenters the confessional, he still does not know what to tell the priest, so he lies that he is a backbiter and a thief.
The first and second chapters of This Boy's Life introduce two of the memoir's major, namely Jack's feelings of guilt and unworthiness, and his desire to transform himself into the boy he fantasizes about being. More than anything, Jack wants to be the privileged, independent boy he describes himself as in his letters to Alice. Jack is determined to impress Alice, his mother, Sister James, and every other person who enters into his life. He makes no attempt, however, to actually realize his fantasies, and can only keep dreaming of transforming himself into the charmed young man he so desires to be. Eventually, these elaborate dreams become Jack's reality, as they are the only thing he can depend on. Even though his elaborate fantasies are untrue, they are a constant source of comfort for Jack, and he relies on them to provide stability in his otherwise unstable life. Ultimately, Jack believes he can make these fantasies real, but he does not yet realize, exactly what such a metamorphosis will take. Jack's visions of himself living an idealized life are what fuel his desire for self-transformation. Jack not only wants to be admirable, but noble and brave, such as the characters he idolizes in the ##Jack London# novels. In changing his name, Jack feels that he is one step closer to becoming the hero he wishes to be, and one step further from his father, who has, until then, caused Jack and his mother nothing but pain and heartache. Jack's feelings of guilt and unworthiness are also a motivator for his visions of himself as a hero. Jack adopts the responsibilities his father has left him with, and wants to provide for his mother and somehow bail them out of their poverty and unhappiness. Jack is only a child, however, and the situation is far beyond his grasp. Therefore, Jack ignores reality and fabricates his own heroics to achieve a heightened sense of self and a feeling of comfort. When Sister James catches Jack aiming his arrow at another boy, Jack is guilt- ridden because he has betrayed someone who was good to him. Subconsciously, Jack makes a comparison between his father's betrayal and his own betrayal of Sister James. Jack's feelings of guilt over betraying Sister James are exacerbated by his fear that he will cause further distress to his mother, whom he wants only to rescue.