"Friendly Rivalry" is a South Korean teen mystery thriller series that premiered on February 10, 2025. Adapted from a webtoon by Song Chae-yoon and Shim Jae-young, the drama stars Lee Hye-ri as Yoo Jae-i and Chung Su-bin as Woo Seul-gi. The story follows Seul-gi, a transfer student at the elite Chaehwa Girls’ High School, who becomes entangled in a complex relationship with the school's top student, Jae-i. As their friendship and rivalry intensify, Seul-gi uncovers dark secrets about the school and her father's mysterious death.