Choi Ja-sil, who lost her childhood faith and was blinded by the world in adulthood, fails in her business. After the successive deaths of her mother and eldest daughter, and being abandoned by her husband, she attempts suicide but finds faith at a tent revival meeting on Mount Samgak. Determined to preach the gospel, Choi Ja-sil enters Sunbogeum Theological Seminary after the age of 40, meets student Jo Yong-gi, and becomes his spiritual mother. After graduating, she starts a tent church in Bulgwang-dong and makes it prosper. Together with Pastor Jo Yong-gi, they preach fervently and move to Seodaemun Church. There, the number of congregants grows, and through tears and prayer, she eventually builds the world's largest Yeouido Cathedral.