Starting with "Suspicious Apartment" in 2014 and continuing to "Suspicious Movie Theater" in 2024, a total of 16 volumes have been published, all of which have quickly become bestsellers upon release. The series is characterized by its mystery format centered around the daily life of an ordinary elementary school girl named Yeo-jin. Each volume addresses social issues that modern children commonly encounter, such as indifference to neighbors, child abuse, food safety concerns, and the importance of community. These elements provide children with an opportunity to question and reflect on how they, as citizens, should engage with society.