Determined to locate his sister-in-law Miku, Fubuki uncovers her involvement in a secretive form of rhythmic gymnastics that tests both elegance and technique. With advice from her classmate Tomomi, he steels himself to serve as a coach in this shadowy competition, aiming to extract her from its influence. This decision brings him into close contact with Fujimiya Koyuki, whom Tomomi has selected as a participant, and as he prepares her for the demanding routines, Fubuki must navigate the mysteries and risks that lie ahead.