In the nostalgic yet mysterious labyrinth of Kowloon Walled City, a place that was once demolished but now stands again, thirty-two-year-old real estate agent Reiko Kujirai lives a quiet life. She works at the Wong Loi Realty Company alongside her easygoing and brash coworker, Hajime Kudou. Though Reiko secretly harbors feelings for Hajime, their days are filled with playful bickering and shared lunches, a comfortable routine set against the backdrop of the city's dense, retro alleyways. This peaceful existence shatters when Reiko discovers a hidden photograph of Hajime standing next to a woman who looks exactly like her, wearing an engagement ring. The discovery triggers a chilling realization: Reiko has no memories of her past. A former acquaintance named Tao Gwen further deepens the mystery by stating plainly, the Reiko Kujirai he knew no longer exists in this world.

As Reiko investigates her own identity, the surreal nature of her world begins to surface. Floating in the sky above Kowloon is a glowing octahedron known as Generic Terra, a creation of the powerful Hebinuma Pharmaceutical conglomerate, which is rumored to be capable of backing up human memories and achieving immortality. Reiko befriends Yaomay, a young seamstress who creates plush dolls and is herself fleeing from her past as the daughter of a famous actress. Together, they encounter the androgynous and serpentine Miyuki Hebinuma, the company’s president, who takes an unsettling interest in Reiko. It is revealed that the Kowloon they live in is not the real one; it is a Generic Kowloon, a reconstruction born from the regret of Hajime Kudou. Three years prior, the real Kowloon was demolished, but Hajime’s overwhelming grief over the death of his former fiancée, the original Reiko Kujirai, resonated with the defective Generic Terra. Using the stored memories of the city and its populace, it generated a perfect, unchanging replica locked in a perpetual summer loop.

The narrative follows Reiko’s desperate struggle to assert her own absolute self, distinct from the ghost of the woman she was cloned from. She learns that most outsiders cannot see Kowloon, and that if an original person enters the replica, their copy vanishes. As Reiko grows more independent and less like the reflection of Hajime’s memory, the simulated city becomes increasingly unstable. Helped by her friends, including a mysterious young woman named Xiaohei and a male version of the same name who investigates the phenomenon, Reiko seeks a way out. In the climax of the story arc, Reiko successfully leaves the boundaries of Generic Kowloon. Instead of disappearing, she steps into the real Hong Kong, leaving the ruined, authentic Kowloon behind to start a new life. The story concludes with a reunion between Reiko and Hajime two years later, suggesting that while the artificial city born from regret has faded, the genuine feelings between them have finally found a place in the real world.