The unbreakable code functions not only as a plot device but as a symbol of the emotional and thematic currents running through the novel. At first, the code seems to represent the thrill of intellectual discovery and the desire for personal achievement. Emily and James both approach it with competitive enthusiasm, seeing it simply as a puzzle to be solved, something that will prove their cleverness or lead to a treasure. As the story unfolds, the novel critiques the idea of working alone to achieve something “unbreakable.” Although Emily is the first to notice key features of the code, it is only through collaboration with James, Ms. Linden, and even James’s grandmother that the code is finally understood. What initially appears to be a symbol of individual brilliance transforms into a symbol of collective effort and shared knowledge.

The code also carries a deeper historical and cultural significance. It was created by a Chinese miner during the Gold Rush, encoded in both English and Chinese and using the Chinese character for hope as a key. This bilingual cipher, meant to be read from right to left, reflects the cultural ingenuity of the miner and the complexities of living under systemic oppression. That the code was long considered unbreakable speaks less to its impenetrability and more to the narrow-mindedness of those who tried to solve it without understanding its context. In this way, the unbreakable code becomes a symbol with multiple layers: It represents not just a challenge to be solved but the resilience, creativity, and invisibility of marginalized people in history.