Sun-woo and Hee-suh, a couple in their 30s, decide to buy a small apartment together. They put all their savings into the purchase, hoping it would be a stable and happy place for them. However, as they move into the new home, Sun-woo loses her job and sustains an injury to her leg. This sets off a chain of events that leads to a strained relationship between them.
As the stress of living together becomes overwhelming, Sun-woo and Hee-suh's relationship begins to fray. Sun-woo is struggling to adjust to life on her own, while Hee-suh is left to shoulder the financial burden of paying the mortgage and interest on their new home. The couple's stress levels reach a boiling point when a foul odor starts to seep into their apartment from downstairs.
The source of the smell is unclear, but it seems to be coming from a neighbor's apartment that has been unoccupied for months. As the couple tries to determine who might be responsible for the smell, they begin to question each other's loyalty and trust.
Despite their differences, Sun-woo and Hee-suh remain determined to find out what happened to their neighbor and make things right. With the help of friends and family, they begin to investigate the situation and uncover some shocking truths about their new neighbors.
As they work to resolve the issue, Sun-woo and Hee-suh must confront their own fears and doubts about their relationship. Will they be able to overcome their differences and build a stronger bond? Or will their past mistakes lead them down a path of heartbreak and disappointment? Only time will tell.