Ishiguro explores loss, power structures, and human dignity amid restrictive social setting. In Remains of the Day and Never Let Me Go, we see the theme of duty also receiving a significant focus.
Remains of the Day explores the decisions Stevens, the butler, makes in serving his employer, Lord Darlington. Darlington is a typical British elite who is also a Nazi sympathizer. Stevens' duty to Darlington hall as an ideal bastion of British propriety blinds him to his employer's shortcomings. This duty also causes him to continue working the night his father dies. Stevens, Sr. also a man utterly dutiful to ideals of service as a butler, is, like his son, a formal man seemingly unable to access his feelings for his son. Duty for both men have veiled all other human impulses. Mr. Stevens' duty also denies him a romantic opportunity with Miss Kenton, a woman who is equally good in her service but who is willing to at least speak her mind about Darlington's anti-Semitism and her own feelings about Stevens.
Never Let Me Go is equally subdued in action but charged with repressed feeling. This science fiction story presents three central characters, Kathy (a carer) and Tommy and Ruth (clones). As the story unfolds, we see that in this world, clones are created to serve their original human, who will harvest organs as needed. The carer tends to the clones during this process, until they are "completed," or die. Kathy fulfills her duty to this system, even as she witnesses both Tommy and Ruth complete their lives by supplying organs to other humans.
In both novels, the sense of duty to a system that is unworthy creates a poignant look at the lives of people who feel they have no control of their lives, no choice in what they do in an unjust and harmful world, and no capacity to give themselves lovingly and independently to another.