There are nearly half a million mentally ill people serving time in America's prisons and jails. As sheriffs and prison wardens become the unexpected and ill-equipped gatekeepers of this burgeoning population, they raise a troubling new concern: are jails and prisons America's new asylums? With exclusive and unprecedented access to prison therapy sessions, mental health treatment meetings, crisis wards, and prison disciplinary tribunals, FRONTLINE goes deep inside Ohio's state prison system to present a searing exploration of the complex and growing topic of mental health behind bars and a moving portrait of the individuals at the center of this issue.