This study will examine a teacher’s educational belief change in the situation of COVID-19. The participant of this study is a Korean teacher who hold 25 years of teaching experience. For the data collection, 5 times of interviews, 1 diary entry, 1 letter to her students were collected. In addition to this, researchers observed the participant’s daily routine in the online teaching context, more than 4 times. With these data, the teacher’s narrative has been studied. The Korean teacher experienced many difficulties. Though she was veteran teacher, it was something difficult to cope with. However, she tried to find the best for her students. There were colleagues and teacher communities, and she interacted with them. Her journey in the COVID-19 situation represented that there were no changes in her teacher belief. Preferably, it was the chance to achieve teacher agency and reconstructing and firming her teacher beliefs.