Nothing is more frightening, as the narrator points out, than a ‘time-rich nosy person’. Exhibit A is Ahn Geo-ul (Gyeong Su-jin), who commits herself to social justice causes with terrifying tenacity. After temporarily renting a unit in the Baek-sae Apartment building, she discovers that a loud, hard to locate banging noise occurs from 4am every night, making the residents’ lives an insomniac hell – and so she determines to engage in her own disruption and to find the culprit of this acoustic assault, simultaneously eliminating her eccentric neighbours as suspects, and recruiting them to her cause. This premise cleverly intertwines personal obsession with collective responsibility, as Ahn transforms from a lone detective into a reluctant community organizer. Her relentless pursuit of the midnight racket becomes a microcosm of the show’s themes: when one person’s “time-rich” curiosity collides with a building’s shared trauma, it sparks unexpected alliances. Viewers can’t help but root for her, even as her methods border on chaos—her single-mindedness feels both infuriating and inspiring, much like real-life activists who refuse to let systemic problems slide. Focusing on a woman who is an unstoppable force for good, it is also a plea for community cohesion and solidarity. The Baek-sae Apartment’s quirky inhabitants—from the paranoid landlord to the reclusive artist—initially resist Ahn’s intrusion, yet gradually find their voices through her relentless quest. This dynamic mirrors real-world struggles: the noise problem isn’t just about a nightly disturbance, but a symptom of how isolated individuals can become when trust frays. By the end, Ahn’s mission evolves from solving a mystery to rebuilding a fractured neighborhood, proving that even the loudest disruptions can lead to the sweetest harmony.