The novel’s unnamed protagonist is a young postal worker who lives with his pet cat Cabbage. The events of the novel span the week following his diagnosis with terminal cancer as he comes to terms with his impending death and grapples with Coming to Terms with Death. In addition to being the main character of the novel, the postman is also the first-person narrator, describing the events of the novel in the form of a long letter addressed to his estranged father. This makes the narration achronological, intercut with flashbacks, dreams, and ruminations.

The postman lives a relatively content but lonely life representative of a particular demographic in Japan of isolated young professionals lacking strong community or familial ties. Outside of work, he spends most of his free time playing on his phone rather than connecting with friends or acquaintances. He is estranged from his only living parent, and his only significant romantic relationship ended seven years earlier. The novel traces the postman’s decision to end this self-imposed seclusion as his character develops. Learning the significance of Valuing Objects, Relationships, and the Everyday by losing access to several mundane things through his deal with the Devil, he reinvests in the people he has lost touch with, finds meaning in mementos he has forgotten, and reevaluates aspects of life that he had initially considered unimportant.