"Residence City 505" is a manga series that revolves around the lives of residents living in a peculiar apartment complex, City 505. The building is home to a diverse group of individuals, each with their own unique quirks, secrets, and interpersonal dynamics. The narrative unfolds through interconnected stories, exploring the relationships and events that bind the residents together.

The central focus is on the interactions between the tenants, who range from ordinary people to those with more mysterious or eccentric backgrounds. Among the key characters is the building's caretaker, who often serves as a mediator or observer of the unfolding drama. Another prominent figure is a young woman who moves into the apartment seeking a fresh start, only to find herself entangled in the complex web of relationships and hidden truths within the building.

The plot delves into themes of isolation, community, and the search for belonging, as the characters navigate their personal struggles and the challenges of living in close proximity to one another. The apartment complex itself becomes a character of sorts, with its labyrinthine layout and eerie atmosphere contributing to the sense of intrigue and tension. As the story progresses, secrets are revealed, alliances are formed, and the residents are forced to confront their pasts and the impact they have on their present lives.

The narrative structure is episodic, with each chapter or arc focusing on different characters while gradually weaving their stories into a larger, cohesive tapestry. This approach allows for a deep exploration of individual motivations and relationships, while maintaining a sense of continuity and progression. The tone of the series balances moments of humor and levity with darker, more introspective elements, creating a nuanced portrayal of human connection and the complexities of urban life.