A prisoner is found dead in his cell and his death is regarded as suspicious. A riot follows and virtually destroys the prison, after two 'lifers' were questioned about the death. Helen Hewitt, who is deputy Governor of a female prison, is requested to become part of an investigation team looking into the mysterious death. Helen is offered the job of the Governor of the prison when the current governor is sacked. She uncovers cover-ups and she strives harder to get the truth.
Barfield Prison is given 60 million pounds to rebuild it after the riot. The prison is currently vulnerable, due to the helicopter wires being taken down due to the damage caused by the riot. A prisoner, Maynard, begins to plan his escape from prison. Meanwhile, another prisoner escapes, but he is then seen by Helen running back to the prison and she learns that he was a long distance running champion and she arranges for him to have regular training. While the prison is sorting out the problems of some of the prisoners, they are unprepared for Maynard and another prisoner to attempt their escape.
Two new prisoners take the places of the escaped prisoners, and work is still underway on rebuilding the prison. Meanwhile, a prisoner is accused of being a sex offender by another prisoner, who insists on a 'court' being held with the accused being on 'trial'.
The prisoners begin to prepare for their trial, each of them being charged with the murder of the inmate who was found hanging in his cell. Fisher, a prisoner, applies for 'home-leave', not mentioning to Helen that his wife has requested a divorce and wants him to sign the deeds on his property over to her. Meanwhile, the trial of the prisoners for murder begins.
Barfield Prison begins to take shape again. Helen introduces the new black officers and they are met with mixed feelings from the staff and inmates. Helen also introduces a psychologist, Maureen Collins, who enlists the help of a prisoner to sort out the library. Alan Fisher is granted his home-leave, but he has some problems when he gets out. Helen discovers that he lied about the reason for his home-leave, which jeopardised his chances to move to an open prison.
The new prison is virtually completed and Helen demands that the new security systems are sorted out soon. The prisoners get drunk and one prisoner is attacked in the showers and his throat cut. Two other prisoners take advantage of the situation and attempt an escape. Helen realises that she could be replaced as the governor of Barfield, and has to fight to get the prison back in order before the Prison Services visit.
Two years after Helen Hewitt lost her position as governor, she has returned to England from America and now teaches Hostage and Siege procedures. Gordon Keller is experiencing problems at Barfield Prison. Morgan doesn't watch his back and he is taken hostage by a mentally ill prisoner, you says he will kill him if his demands are not met.
Maureen Collins brings in two actresses for a production of the Pirates of Penzance. A prisoner begins a relationship with one of the actresses and Maureen Collins is brutally raped by an inmate. Helen Hewitt returns to the prison to the public outcry the rape has caused.
A prisoner hatches a plot to escape and goes with his wife to the Lake District. Helen is told by the police that they have a tip off, and he is recaptured in Leeds. After breaking a chair over an officer's head, he gets a beating and is sent to the hospital wing. Helen begins an inquiry into whether one of her own officers beat him up.
Helen begins to look into the incident of the escaped prisoner. She interviews other prisoner and the prisoner is attacked. It is 'proven' that the officers attacked in self-defense, and the prisoner decides not to press charges - else his life in prison would be awful for the next eleven years. He meets Victor Braithwaite and asks him if he can be involved in whatever he is planning against the officers.
Victor Braithwaite carries out his plan and takes Officer Morgan hostage and holds him inside a cell at knife point. He makes demands and Helen tries to talk to him, but the prisoner inside the cell with him gets a kicking when he tries to release Morgan and Braithwaite refuses to allow either of them out of the cell.
Officer Morgan returns from his home-leave after the hostage situation. Helen leaves the prison on a training course and the prisoners plan their biggest escape attempt yet. A prisoner holds all the officers as everyone escapes and Marshall is shot down. Helen feels responsible for what has happened even though she wasn't there and feels she has failed in what she tried to accomplish at Barfield Prison.