In a distant future, those who cherish the traditions of the past have settled in Kowloon Walled City—a densely populated slum that preserves the spirit of old Hong Kong. Among them is Reiko Kujirai, a real estate agent with a thirst for novelty and modern experiences. Her colleague, Hajime Kudou, feels quite the opposite—he’s deeply attached to the nostalgic atmosphere of the city and avoids anything that feels too contemporary. Although their perspectives often clash and lead to frequent arguments over trivial matters, they unexpectedly grow fond of each other’s company.

However, when a harmless prank takes an unexpected turn, Hajime impulsively makes a move on Reiko—only to quickly apologize. Confused by his behavior, Reiko begins to search for answers, uncovering a forgotten past that she can’t seem to recall.