The Remains of the Day tells, in first person, the story of Stevens, an English butler who has dedicated his life to the loyal service of Lord Darlington (mentioned in increasing detail in flashbacks). The novel begins with Stevens receiving a letter from a former colleague, Miss Kenton, describing her married life, which he believes hints at an unhappy marriage. The receipt of the letter coincides with Stevens having the opportunity to revisit this once-cherished relationship, if only under the guise of investigating the possibility of re-employment. Stevens's new employer, a wealthy American named Mr Farraday, encourages Stevens to borrow his car to take a well-earned break, a "motoring trip". As he sets out, Stevens has the opportunity to reflect on his immutable loyalty to Lord Darlington, on the meaning of the term "dignity", and even on his relationship with his own late father. Ultimately Stevens is forced to ponder the true nature of his relationship with Miss Kenton. As the book progresses, increasing evidence of Miss Kenton's one-time love for Stevens, and of his for her, is revealed.
Working together during the years leading up to the Second World War, Stevens and Miss Kenton fail to admit their true feelings towards each other. All of their recollected conversations show a professional friendship which at times came close to crossing the line into romance, but never dared to do so.
Miss Kenton, it later emerges, has been married for over 20 years and therefore is no longer Miss Kenton but has become Mrs Benn. She admits to wondering occasionally what a life with Stevens might have been like, but she has come to love her husband and is looking forward to the birth of their first grandchild. Stevens muses over lost opportunities, both with Miss Kenton and with his long-time employer, Lord Darlington. At the end of the novel, Stevens instead focuses on the "remains of [his] day", referring to his future service with Mr Farraday.