In the 1830s, the Paris Foreign Missions Society, France's first foreign mission society founded for the purpose of missionary work in Asia, dispatches missionaries to Joseon for the first time. However, the three priests Maubant, Chastan, and Imbert are all martyred at Saenamteo, and nine more priests who entered Joseon afterward are also martyred… The records of time that we didn't know are revealed!