She opened her eyes and found herself reincarnated as a supporting character who fell due to a momentary mistake. "So I, who am neither the protagonist nor a rich heiress, but a simple extra who only appears to cause a big accident!" The only way for 'Elena', a humble divine servant, to escape forced slavery was hide her commoner identity and become a theology teacher for the emperor's younger brother. Since it was like that, she thought about watching the triangular romance between the protagonist, the teacher 'Rosaline' and the male protagonist, and end up settling down with him. "Were you really a commoner?" She is faced with Rosaline's terrifying face at the same time that her identity is revealed. But... does she start to get involved with the male protagonists while replacing Rosaline in her duties? Wait, but that's the protagonist's role! But despite their fierce approach, Elena only has eyes for the insignificant apprentice knight she met by chance.