Broken Walls Paperback (Book 5)

After betrayal at his friend's hands, SC travels deep into the heart of the Instructors - coming not as an enemy, but as an ally. With his memories still modified by Lucio, he joins their ranks with a single goal in mind. To free Siri, the Titan whose songs bends others to her will. Meanwhile, SC's friends rush to stop him, and to understand why SC is suddenly acting insane. With his mind altered, and his powers honed by the instructors, rescuing SC will take everything they have.