The escape is on and there is tension in the air and not everything goes according to plan – but as some escapees find out, getting out of Colditz is only one part of the battle – getting out of Germany proves to be much more difficult.Flt-Lt Carter has been caught trying to escape but has managed to pass on valuable information which has made a previous escape plan possible. Captain Grant has been relieved of his duties as Escape Officer to lead them.

Mc Donald, a Scottish officer, receives a ""dear John"" letter and wants to escape desperately to put things right at home which puts the escape committee in a spot. Phil Carrington befriends the man and does what he can to help, but McDonald is tall and loud and stands out in a crowd – will anyone want to escape with him?

The prisoners can now see battle activity from the upper reaches of the castle, but there is strong SS resistance and Colditz comes under attack. Phil Carrington makes a break for American lines, but the situation is very confused and there are many obstacles to pass before Colditz can be truly liberated.

When a lorry drives into the Castle courtyard, Captain Grant seizes the opportunity to put a blitz escape operation into action.

One of the German guards is found murdered, but fearing reprisals from the Gestapo, the Kommandant reports it as suicide. The Gestapo decide nevertheless to investigate but at the same time, Colonel Preston asks Simon Carter to look for a murderer among the prisoners and clues indicate that Simon may have his hands full.

A new doctor joins the German staff at Colditz and his stickling for rules causes problems with the prisoners, but then Simon Carter sees this as an opportunity to be court-martialled which means being sent to Leipzig where there is a better chance to escape, but things don't go as planned and soon Simon is in danger.

Wing Commander Marsh assists the British doctor as an orderly and he proposes escaping by feigning mental illness in order to be repatriated. The escape committee is not told of the plan and Marsh starts acting irrationally – however, the ever suspicious Ullmann appoints Private Hartwig to watch Marsh. Hartwig has a mentally disturbed brother and knows exactly what to look for. Will the wing commander be able to live the part and convince him?

Colditz gets a new senior British officer, Colonel Preston (Jack Hedley). (The previous senior British officer, Major Donaldson is referred to in this episode but never seen). On his arrival he witnesses a futile escape attempt by Flight Lieutenant Carter and when the Kommandant meets him, he believes Preston is a man of honour who he can deal with. The colonel's new orders that seem to be appeasing the Germans cause conflict and dissension in the ranks, but there is method in the colonel's madness, which could come unstuck when a Polish officer decides to escape.

The opening episode takes place in June 1940. Captain Pat Grant (Edward Hardwicke) is captured and taken to a camp where he immediately starts organizing escape activity. After an unsuccessful escape he is sent to Colditz.

The bruised and unconscious body of submariner Lieutenant Dick Player is washed up on a beach somewhere in France. He is wearing plain clothes and speaks fluent German, which makes his captors believe he may be a spy. He escapes from the hospital where he is taken to recover but is recaptured and interviewed by the Gestapo. Player had once lived in Germany as the son of a diplomat and manages to get to speak to a childhood friend – now an important government official who offers Dick a chance to work with a plot to overthrow Hitler, but at a price.

Action takes place in May 1940. After having a disagreement with his new wife, Flight Lieutenant Simon Carter (David McCallum) sets off for a night mission over Germany but he is forced to bail out of his crashing aircraft. On the ground, he befriends a young priest but the Gestapo arrests them both. Carter escapes first from the Gestapo and then from the prisoner of war camp he is assigned to – from there he is despatched to Colditz.

Colonel Preston receives bad news from home and has to make a decision about his command. Meanwhile Dick Player has to go to the dentist in town and gets set to escape, but while there he finds out information which could assist in a mass escape. It all depends on being able to bribe one of the guards, Private Heller – but will he play ball?

The town jail is being used as an overflow for Colditz prisoners and while Dick Player is there he observes an intake of three new prisoners – but these men are British commandos and Hitler has given instructions for all commandos to be shot. An escape plan is hatched using the best route – but Major Mohn is taking more than a passing interest in these commandos and has ideas of his own.

Dick Player comes up with an escape idea that would involve going through the disused theatre, but things do not go according to plan when it seems the French have the exact same idea. Mohn is still investigating the last British escape and he is beginning to get close to the truth – but can Simon Carter divert his suspicions in a psychological chess game?

Colditz has a choir and they are asked by the local pastor to sing in his church for the Easter service. Captain Vaillant sees this as a means of escaping in order to avoid being transferred to Poland with the rest of the French contingent. Meanwhile a secret radio is bringing news of the war to Colditz.

A trio of Americans arrive at Colditz to join the solitary US inmate, Jim Phipps – but his suspicions are aroused when he sees the newcomers getting access to American newspapers and better provisions and despite the fact that there is a familiar face, the British wonder if in fact they are housing a German trained fifth column.