Welcome to Emerald City, an experimental unit of the Oswald Maximum Security Prison or "Oz." As run by Tim McManus and overseen by Warden Leo Glynn, Em City is about prisoner rehabilitation over public retribution. No matter how hardened a criminal or killer, whether you're in for a few years or in for life, you have a role to play. Once inside, choose your friends carefully. Every group -- Muslims, Latinos, Italians, Aryans -- stick close to mutual friends and terrorize mutual enemies. Don't smile. Get yourself a weapon. Stay on everybody's good side... if you can find one.