Major renovations follow the gas explosion in the kitchen; the prisoners from solitary return.
Alvarez and Schillinger are put back in the general population; the new librarian lifts Rebadow's spirits.
Redding and Morales forge an uneasy defensive alliance; Keller returns; the Cloutier mystery deepens.
Penders, Hill and Alvarez train Seeing Eye dogs; Nathan and Howell have a heart-to-heart talk; Schillinger's gripe with Said turns deadly.
The unexpected arrival of the mayor spurs an ironic turn involving Schillinger and Beecher; Dr. Nathan discovers why solitary inmates are getting sick.