Rika, an athlete striving to compete in international freediving competitions, pushed herself to the limit through grueling training. Unable to endure the intense pressure and mental strain, she fired her coach. This decision drastically alters the course of her life. The dismissed coach, consumed by vengeance, begins to stalk and torment Rika. In the process, she is forced to confront her own limits and the darkness within her mind. The story portrays her harsh reality and inner struggle with self-annihilation.