The narrator, Death, introduces himself in four sections, the first of which is "Death and Chocolate." In this section, Death discusses the importance of colors and how he sees colors before he sees humans. He describes their murkiness and how they run into each other, one after another. He also establishes the main events of the story that he's preparing to tell.
The next section is "Beside the Railway Line," which opens with white as the focal color, an emphasis on the snowy setting. Beside the railway tracks are a mother, a daughter, and a corpse. Two train guards discuss what should be done with the three; they need to get them back on somehow but aren't sure how. While the guards debate, Death admits that he now knows he made a mistake in lingering because he became so curious about the girl, the book thief. That was the first time he saw her.
He describes the second time he sees her in the next section, "The Eclipse." A pilot crashes and Death comes to take his soul from the cockpit. The focal color is black. While Death waits for the pilot to die, a boy comes to the plane and pulls a teddy bear from a toolbox and places it on the pilot's chest. With the boy is the book thief, a few years older, but Death knows it's her.
In "The Flag," the focal color is red. During the bombing of a German town, he sees the girl kneeling in the street amid the devastation, holding a book to her chest. He follows her, and she drops the book. It gets thrown into a garbage truck, and Death takes it. He remembers the book thief in colors, primarily in red, white, and black. He says that he carries certain stories with him, stories that convince him of the worth of human existence. The book thief's story is one of those, and it's one he wants to share.
In the Prologue, Death establishes the main events of the story. He identifies the book thief and the moments during which he sees her throughout the course of her life. Death provides glimpses of the story's future but doesn't narrate in detail, something he will do as the novel progresses.
Each of these events coincides with a particular color that reflects the mood of the moment. Throughout the novel, Death's preoccupation with and study of colors remains a consistent theme. He comments frequently on his inability to understand humans, how they can be so kind and yet still cause so much destruction and suffering; like colors, humans are ever-changing and can also be murky in their behavior. Along with the mood of the humans, the colors often complement the weather, as well as the tone of the events happening during particular chapters. For example, Death emphasizes the color white during the snowy scene in "Beside the Railway Line" when Liesel's brother dies, linking the color back to the weather, thus contributing to the overall setting. Also, Death focuses on the color black, a color of mourning and sadness, during the death of the pilot in "The Eclipse," contributing to the scene's stylistic tone. This pattern of having colors, moods, weather, and tone complement each other continues throughout the novel.