As the attentiveness of the new librarian raises Rebadow's spirits, Schillinger and Alvarez return to the prison's general population.
As Dr. Nathan finally figures out why inmates in solitary have been getting sick, the mayor's unexpected arrival leads to an ironic development with Beecher and Shillinger.
As Cyril O'Reily is subjected to an unconventional form of therapy, Officer Brass has a meaningful encounter with Morales. Meanwhile, Schillinger's meeting with the Mayor doesn't go quite as he'd hoped it would.
As Robson gets redemption at long last and Glynn gets a mixed report on the poison problem, Beecher and Keller come to an understanding.
As Morales receives verification of her medical suspicions and Alvarez gets some shocking news, Murphy admits a secret to Glynn and Redding continues battling.
As the inmates join forces to support the O'Reilys and a hitch develops in the Muslims' business, Idzik faces down his enemies and asks to be transferred.
An unexpected discovery caps off an awards banquet; Oz receives three new inmates; Rebadow and Busmalis prove to be major Lotharios.
As Alvarez accepts an irresistible offer and Howell and Robson face bad health news, Martin Querns's return throws the prison into turmoil.