The Last Samurai is about the relationship between a young boy, Ludo, and his mother, Sibylla. Sibylla, a single mother, brings Ludo up somewhat unusually; he starts reading at two, reading Homer in the original Greek at three, and goes on to Hebrew, Japanese, Old Norse, Inuit, and advanced mathematics. To stand in for a male influence in his upbringing, Sibylla plays him Akira Kurosawa's Seven Samurai, which he comes to know by heart. Ludo is a child prodigy, whose combination of genius and naïveté guide him in a search for his missing father, whose identity Sibylla refuses to disclose — a search that has some peculiar byways and unexpected consequences.
The novel starts with a prologue which outlines the early life of Sibylla, the main character's mother. It brings up the theme of the importance of education, a theme which runs throughout the entirety of the novel.
The beginning of the novel is told in the perspective of Sibylla, as she gives the reader background as to her relations with Ludo's father. The novel then progresses to see Ludo at ages three and then six. During these scenes the reader watches Sibylla teach her son a variety of languages, including Greek, Hebrew, then Japanese and even Inuit. The young single mother also teaches her son complicated mathematics, which he masters with ease.
The next portion of the novel describes Ludo at age eleven, with no formal schooling and the only social interaction he has coming from his participation in a Judo class which his mother has enrolled him in. For the first parts of the novel the reader only sees the interactions between Ludo and his mother, however Sibylla becomes increasingly absent during the second half of the novel. Instead, Ludo replaces her involvement in his life with the pursuing of various potential fathers. Ludo interacts with several adult male geniuses, testing each of which to see if they would make a good candidate to be his father, as when he finally does meet his father he deems him undeserving of having Ludo, due to his lack of intellect.
Throughout the novel the reader sees Ludo mature and grow up, switching roles with his mother and become more of her parental figure than vice versa. In the end the boy has matured into a genius who has learned much about both life and death.
One of the major aspects of the novel is the character development, especially Ludo's. In the beginning of the novel, Ludo is very dependent on Sibylla. As a single parent, Sibylla is the one who decided how she should raise Ludo, deciding that having Ludo study so many different academic works was what was best for Ludo. However, Ludo eventually took steps to become more independent. For instance, when Sibylla refuses to tell Ludo who his father is, Ludo takes steps to find out, searching through his mother's belongings to find out the true identity of his father. When Ludo finds out who his father is, he seeks his father by himself. After meeting his true father, Ludo decides to make decisions for himself, creating an ambition to become the best by searching for the "best" father. Ludo's maturity is shown through his independence in journeying for different fathers. Sibylla's absence in Ludo's search for a father further highlights the growth of Ludo, who had become more mature despite being only eleven years old. Another development shown through Ludo is his change in mentality. Due to Sibylla's influence, Ludo had a narrow mindset, focusing solely on academics. He only thought of academics to help his image, having large ambitions to become the best, such as wanting to go to Cambridge at the age of eleven. In addition, he only wanted a father that was extremely prodigious because it would help him. However, during his journey to find his father, he starts to lessen his expectations. In the end of the novel, he manages to develop a connection with Yamamoto, not for the fact that he was extremely talented but because he was the one to whom Ludo could have a logical connection through conversation.
Throughout the entire novel the reader sees Sibylla and Ludo watch the film, Seven Samurai. The film is regarded by Sibylla as a masterpiece, and she consistently relies on the film to be a source of escape for herself. She uses the film to give Ludo potential male role models, as he is lacking fathers, uncles etc. in his life. Throughout the novel references are made to the film, and Ludo compares the males he comes into contact with, to the samurai, testing the mettle of each one.