The suspect in the 'Seo In Hui Murder Case' that occurred in a public apartment complex is the victim's friend, fellow teacher, and single mother, Han Ji Eun, who lives in the apartment complex. The police continue to corner Ji Eun as a suspect, and her daughter Na Eun, who witnessed the culprit, is threatened by someone. With the help of Pil Seong, a former detective and apartment security guard, Ji Eun begins to track down the real culprit and clear her name. The hidden stories related to Seo In Hui's death are revealed. (Source: Korean = tcokr.com || Translation = MyDramaList)