The main theme is about mortality and making the most of the time one has left. It shows how two strangers, upon learning that they will die at the end of the day, choose to experience life in different ways.
The central theme in this novel is mortality and seizing the day. The story of Mateo and Rufus serves as a poignant exploration of how we deal with the knowledge of our impending death. It's not just about death, but also about the relationships we form, the experiences we seek, and the growth we can achieve even in the face of death. Throughout the novel, we see how Mateo, who is shy and reserved, and Rufus, who is more brash, come together and change each other's perspectives in their last day. This shows that even in the short time they have left, they can still make an impact on each other's lives, which is a powerful message about the value of human connection in the face of mortality.