All Fletcher wants is a quiet Christmas, but one of Groutie's friends is building a tunnel out of Slade Prison, the tunneling noises being drowned out by the prison Choir. Anxious to keep his nose clean, Fletch is desperate to get into the prison hospital before the escape plot is discovered, so he conjures up an injured right knee - or is it the left knee? As fate would have it, Groutie is determined that Fletch should be at the centre of things, even going so far as to pick up a blank passport on his day out of the prison to get his injured right - or should that be left? - knee X-rayed.
Barrowclough and Mackay discover Fletch is cooking up some home brew, and the crafty con seems certain to spend Christmas in solitary confinement.
Some pills are stolen from the surgery by Harris and when Mackay searches him he manages to get rid of them. Fletcher is told by Grout to make sure they are replaced so that his pill-peddling racket will remain uncovered.
Fletcher's new cellmate ends up being the judge who sent him to prison.
After Judge Rawley's watch is stolen, Harris is the only suspect. A kangaroo court is set up as Harris is put on trial.
After Blanco is given parole, he refuses the chance to be released. He demands that he be pardoned as he never killed his wife and leave prison with his name cleared.
Godber is trying to gain an O - Level in history. Fletcher thinks it is a waste of time but he still wants to help Godber pass his exam. Fletcher, Warren and McLaren decide to steal the exam paper so that Godber will know the questions in advance. The problem is they send in Warren to steal the exam paper bu he can not read.
Godber ends up getting involved in a brawl just before he is due to face the Parole Board which could damage his chances of being released from prison early.