With the performance approaching, the third son, Mizuki, disappears from the practice field. Though more hardworking than anyone else, he harbors a deep inferiority complex toward his genius-like older brothers. Despite his leg injury, he continues his solitary training. "I don't want to lose to Fumino and Shori." This is the first time he's confessed his desire, not as a member of Trinity, but as an individual performer. Meanwhile, Hitomi, a girl who admires the three, is about to make her debut. She's paralyzed by nervousness and stands frozen on stage. Mizuki, limping, saves her from this predicament. Enduring the intense pain, he encourages Hitomi, telling her to "believe in yourself." He has grown into a strong presence, not just a little brother to be protected by his older brothers, but someone who pushes others forward. Just as the three begin to unite in spirit, knowing Mizuki's resolve, they receive tragic news: an accident at the reserved venue has forced it to be banned. Deprived of their right to fly, the birds face their greatest challenge yet.