Through the characters of Lee Young-sup and Lee Kee-sup, Park explores the power of family and brotherhood, while also examining the difficulty of navigating tense relationships. Over the course of the novel, the brothers’ relationship undergoes significant changes: Once Kee-sup is capped, it fundamentally changes his place in Korean society, and societal norms require Young-sup to engage with him differently. The older they get, the more their birth order matters, which they both resent but cannot do anything about.

Neo-Confucianism also strictly relegated women to the home, and though wives and mothers were fundamental in running a household, their work and individual identities are nearly invisible in the novel, mirroring the real historical lack of acknowledgment Korean women experienced. The extreme patriarchal structure meant that a father had absolute authority over his family, which Young-sup and Kee-sup accept without question. As Kee-sup and Young-sup learn, the loyalty expected for the father or for an elder can conflict with loyalty to another, or even to oneself. This creates tension between the brothers and their father, but despite Young-sup’s doubts, Kee-sup demonstrates his utmost loyalty and love for him by questioning their father’s request and advocating for Young-sup to fly.