In the 'Emerald City' experimental unit of Oswald State Penitentiary, we meet some of the diverse inmates who exist in a pecking order of Gangbangers, Latinos, Muslims, Westies, Aryans and Wiseguys.

Ricardo is discovered to suffer from Alzheimer's; Beecher flips out and sends Schillinger to the hospital; mob boss Schibetta develops stomach problems thanks to some ground glass; and Said has a heart attack.

A recovered Said ostracizes Huseni Mershah for turning his back on him when he was dying--and orders all the Muslims to cast him out. Impressed by Said's power, Groves decides to kill Glynn in his honor, but ends up stabbing an officer by mistake.

Ten months after the riot, Em City is reopened. A recovered McManus creates a council of group representatives to keep order, and initiates classes to help inmates get high-school equivalency diplomas.

Alvarez knows who raped Glynn's daughter, but refuses to tell the warden. Wangler is making progress at school, but his cellmate, Adebisi, isn't a fan of higher education. When Hill's judge is convicted of accepting bribes, Said takes up Hill's case.

Augustus Hill's appeal is denied, despite the efforts of Said, who has better luck with Poet's poems. Meanwhile, O'Reily survives his lumpectomy, and now focuses his attention on Dr. Nathan.

With their enmity at a boiling point, Adebisi poisons Schibetta--but not fatally. Now that his brother has turned himself in for murder, Glynn no longer owes Schibetta any favors.

Schillinger attempts to enlist Said to get him out of jail. Recovered from being poisoned, Schibetta is brutalized by Adebisi, losing 'control' of Oz. Meanwhile, Alvarez is bumped out of the Latino power seat by Raoul Hernandez, a.k.a. El Cid.

Cyril O'Reily, Ryan's brother, is imprisoned and falls under Schillinger's control. Ryan tries to get him away into Em City, but Cyril winds up in the hole. El Cid tells Alvarez there's only way he can 'stay in the game.'

In the Season Two finale, Wittlesey is transferred to general population and replaced by Karl Metzger, a Nazi. Mack and another Aryan try to escape through Busmalis and Rebadow's hole. Hill gets the idea of escaping Oz by hiding in a coffin.

In the Season Three premiere, Beecher is still in the hospital after Schillinger and Keller broke his bones, Alvarez is still in solitary for blinding Rivera, Adebisi is back in the kitchen and McManus starts dating a newly arrived CO.

No one knows who killed Metzger. Meanwhile, McManus hires his friend Sean Murphy as a C.O. and he launches a boxing program. Hill faces a dilemma when a new inmate reveals a terrible crime. Adebisi sticks Nappa with an AIDS-infested hypodermic.

In the boxing program, O'Reily spikes Robson's spritzer bottle before his bout with Cyril. Rebadow's mother tries to persuade him to meet his son and grandson. Meanwhile, Nappa finds out he's HIV-positive and is moved to Cell Block E.

O'Reily and Keller plot to take care of Andrew. McManus is forced by prison brass to settle Howell's sexual-harassment suit. Hanlon's murder convictions get overturned and he's allowed back in the general population--where he finds new troubles.

Wangler 'finds out' his wife and her lover were murdered execution-style. Meanwhile, Poet and Pierce get burned by Hernandez, Ricardo and Guerra. Lockdown ensues, and Wangler finds himself vulnerable--and in a cell with Adebisi.

With Cyril scheduled to box Pancamo, O'Reily plans to use his spray-bottle trick, but first he must deal with Cudney. Alvarez sees the photos of Rivera's gouged-out eyes and goes nuts. New roommate Nat Ginzburg offers to be Nappa's secretary.

Brace yourself for the explosive Season Three finale! As the new millennium approaches, things are heating up in Em City as racial tensions mount. Glynn fires Hughes, but before leaving, Hughes delivers a millennium gift to Adebisi: a gun.

Season Four premiere. The world of Oz--an experimental prison within a prison known as the Emerald City--reopens its doors with the inmates still on a 24-hour lockdown and prison officials struggling to end the hostilities.

The African-American inmates point the finger at McManus for letting Em City get out of hand. After that and his recent erratic behavior, McManus gets the ax from Glynn. Mobay's cover is almost blown.

Glynn learns from Adebisi that he was given the gun by former C.O. Hughes. Morales enlists Rebadow's help in taking Hernandez's place in the drug ring run by Adebisi and Pancamo. Mobay finds himself in a dangerous position.

Em City gets a new Unit Manager, Martin Querns, whose methods are hardly orthodox. Beecher's torment over his missing children is worsened when Schillinger presents him with an unexpected package. McManus returns to Oz in a new capacity.

As Querns implements his new course of action, the dynamics of Em City start to change, causing friction with Officer Murphy. Beecher falls deeper into depression as he wonders about the fate of his children.

In an effort to reduce violence, white inmates are transferred out of Em City. Said and Arif talk to Querns about the negative impact of his changes, but their efforts are in vain. Mobay gets in good with Adebisi's crew...but pays a price.

With things wild in Em City, O'Reily begins a surprising affair. Zabitz asks Schillinger for protection from Keller--who tries to get into the rehab program to make amends with Sister Pete. Beecher looks to get even with his children's kidnapper.

After Hughes' attack on Devlin, Glynn withdraws from the race. Miguel Alvarez is still on the loose. Supreme Allah receives an unwanted surprise. Hill pays big time when he tells Mobay he knows he's undercover. Meanwhile, Said does the unthinkable.

Six months have passed. Said was acquitted of Adebisi's murder on grounds of self-defense. "Up Your Ante," a game show, has joined Miss Sally in the prisoner's TV lineup. McManus and Glynn have done their best to keep the events leading up to Adebisi's death a secret. News producer Lisa Logan tours Oz in preparation for the arrival of hard-hitting reporter Jack Eldridge, who will also be spending a night with the new inmate the cameras will follow around on his first day. That man is Omar White, a jittery, homophobic addict fiending for drugs. Busmalis drives the cameras away. After an interview with Beecher Lisa considers focusing the piece on his struggles in Oz. Beecher taunts Keller and Ryan with on camera hints of their involvement in the murders; Keller threatens Ryan when Ryan wants to deal with Beecher; Pete dodges questions; Tidd interrupts a tense moment between Lisa and Vern. After a mention of Adebisi's drug-and-sex videotapes by Poet, Lisa decides to make the piece about the mystery surrounding his final days. Eldridge arrives, digging for information on Ryan after Ryan hints at their past connection. Eldridge blindsides Said with questions about his part in Adebisi's death. Worried about damage to Em City and his and Glynn's careers, Tim points Lisa toward the man he blames: Querns, who kept quiet in exchange for Glynn keeping quiet over his unethical methods. Per Glynn's advice, Querns turns down requests for an interview; per Querns' advice, Glynn destroys the tapes. Glynn and Jack have an off-the-record conversation, leading Eldridge to realize Glynn was a good man caught up in a situation he couldn't control. Jack cancels the Adebisi story. Offering him a constant supply of drugs, Ryan manipulates White into helping him settle an old score against Eldridge. Unfortunately, White tries to attack Eldridge directly in front of the guards. White goes to solitary. Eldridge chooses Cyril for his podmate, sensing good story potential. Cyril, who hasn't been taking his medication, remembers Eldridge and blames him for his mother getting cancer (Eldridge did a piece on Ryan on Cyril when they were in charge of their local Irish gang, painting them as monsters. Their mother developed and died from cancer not long afterward.). Cyril beats Eldridge to a pulp. As he recovers from serious injuries, the network decides to cancel the piece on Oz. Lisa resigns in protest.

New inmate Burr Reading arrives, ready to take charge of the African-American drug scene. Dr. Nathan returns to Em City, and finds the biggest adjustment is dealing with her feelings for O'Reily. Tidd tries to strike up a deal with Schillinger.

Morales looks to pit the Chinese against Redding. Alvarez offers Glynn his services as an informant as a way out of solitary. Dr. Nathan announces that Em City inmates will be selected to test a trial drug that could reduce their time behind bars.

O'Reily regrets getting Cyril involved with the trial drug when it starts taking effect. Meanwhile, Giles' request for an unusual execution creates controversy and the Chinese refugees are deported...but not before plotting revenge on Morales.

O'Reily is in for a surprise when a visitor reveals the truth about his past, while Cyril faces trouble for his difficult behavior. Meanwhile, Morales and Redding lay out plans that could lead to all-out war in Em City.

McManus calls a superficial truce between Redding and Morales. Basil finally sees his wife, but Hughes ends up spoiling their happiness. Meanwhile, Cyril's latest outburst proves to be the last straw.

McManus can't turn his back on White. Beecher tells the parents of the girl he killed that he's up for parole. Howell tries to blackmail O'Reily so she can get to Cyril, but he throws her for a loop--and then O'Reily is thrown himself by a secret.

In the Season Four finale, Hill discovers where his true allegiances lie in Oz. Redding's plot to use the Colonel against Morales has an unexpected outcome. Beecher's agony about his parole hearing leads to a shocking season climax.

In its fifth season premiere, Oz re-opens in the wake of major renovations that had to be completed following a gas explosion.

McManus thinks White may reform if he spends quality time with Said; Alvarez offers Guerra a unique solution to their dispute; O'Reily's mother, Suzanne Fitzgerald, begins a community service term teaching music at Oz.

Brass wants to know who cut his tendon; Redding and Morales form another uneasy alliance; Rev. Cloutier's mysterious influence over his followers grows more intriguing; and Keller returns to Oz, only to be hit with an ID from an old murder charge.

Penders, Hill and Alvarez are given a chance to train seeing-eye dogs; Martinez gives Brass a 'cocktail' he definitely didn't order; the love triangle between Beecher, McClain and Keller becomes more complicated.

Robson stirs up problems between White and Said. Meanwhile, Pancamo's illness might save some work for his enemies, Schillinger makes a friendly but suspicious overture towards Beecher, and Morales seeks revenge on his sister's abusive husband.

As Cyril's trial gets off to an inauspiciously cold start, tensions between Mukada and Kirk come to a boil. Also, a priest named Meehan lands in Oz while White and Said turn over a new leaf in their relationship.

Hill's recovery leads to renewed friction between Redding and Morales, Alvarez gets his wish as the 'Man's Best Friend' program is finished and Meehan presents some revolutionary ideas to help Cyril.

In the Season Five finale, Robson goes to extremes to remedy his gum dilemma, Meanwhile, McManus struggles with personal turmoil over his decision to stay at Oz and Rebadow deals with his grandson's fate.

In the Season Six premiere, Alvarez and Schillinger are let out of solitary and placed back in general population. Meanwhile, a mourning Rebadow's spirits get a lift when he is transferred to the library and meets the new librarian, Stella Coffo.

The unexpected arrival of Mayor Loewen at Oz spurs an ironic turn involving Schillinger and Beecher. Meanwhile, Dr. Nathan discovers why solitary inmates are getting sick. A new business plan within Oz inspires Redding.

Tobias learns who killed his father before being released from prison. Cyril begins shock therapy while receiving an execution date. Said is allowed to start his own company.

Glynn receives mixed news on the toxic-poisoning problem. Meanwhile, Rebadow's relationship with the new librarian Stella hits a snag, Keller and Beecher work out an agreement, and Robson finally gets some redemption.

Arif and the others have trouble getting Augustus' book published. Tobias confesses to Chris he's started dating someone on the outside.

New inmate Idzik faces his enemies and requests a transfer. Meanwhile, the Loewen case grows increasingly complicated, the Muslims run into business trouble, and the inmate population comes together to support the O'Reilys.

Three new inmates arrive at Oz, one of whom is particularly close to the O'Reily clan. Meanwhile, the Keller-Beecher-Schillinger triangle gets even more pointed, and an awards banquet ends in a fateful discovery.

Querns is appointed the new warden of Oz. Brass attempts to get famous for a day. Tim tries to change the mindset of Said's murderer. Cyril is finally executed. Keller brings Tobias back to Oz for good.

With their enmity at a boiling point, Adebisi poisons Schibetta--but not fatally. Now that his brother has turned himself in for murder, Glynn no longer owes Schibetta any favors.

In the 'Emerald City' experimental unit of Oswald State Penitentiary, we meet some of the diverse inmates who exist in a pecking order of Gangbangers, Latinos, Muslims, Westies, Aryans and Wiseguys.

Augustus Hill's appeal is denied, despite the efforts of Said, who has better luck with Poet's poems. Meanwhile, O'Reily survives his lumpectomy, and now focuses his attention on Dr. Nathan.

Cyril O'Reily, Ryan's brother, is imprisoned and falls under Schillinger's control. Ryan tries to get him away into Em City, but Cyril winds up in the hole. El Cid tells Alvarez there's only way he can 'stay in the game.'

McManus can't turn his back on White. Beecher tells the parents of the girl he killed that he's up for parole. Howell tries to blackmail O'Reily so she can get to Cyril, but he throws her for a loop--and then O'Reily is thrown himself by a secret.