Limo comes of age in a late-1990s Shanghai shikumen neighborhood, inseparable from childhood companions Pan and Xiao Yu. When Xiao Yu sprains her ankle on a fractured pathway near their homes, he carries her back, sparking an intimate bond. They forge a secret language through exchanged cassette tapes—Limo recording school lectures to aid her recovery—which gradually blossoms into a romance anchored in whispered insecurities and steadfast encouragement.

Driven by Xiao Yu’s family mandate to attend an elite high school, Limo dedicates himself to academic rigor, securing admission only to learn she failed the entrance exam and suffered a brutal beating from her father, leaving her hospitalized. Denied a farewell, he relocates with his family near the new campus, severing their tie.

Years later, as an architect, Limo converts a shikumen into a guesthouse. Amidst renovations, he unearths an unplayed cassette from Xiao Yu. The tape confesses her intentional exam failure to remain with him—a revelation sharpening his decades-old regret. When Xiao Yu reappears at his guesthouse, tentative steps toward reconciliation begin. Their unresolved story lingers until a post-credits airport encounter years later, hinting at rekindled hope.

Limo’s life echoes a tension between loyalty to relationships and a youthful reticence that prolongs separation. His path mirrors the weight of roads untaken and the indelible imprint of adolescent choices, with cassettes serving as silent witnesses to both closeness and the hollow ache of what might have been.