Every day sees an increase in the number of RAF prisoners of war at the camp, and among them is an enigmatic flying ace who takes on the position of their senior officer.

It is every officer’s responsibility to try to get back to his unit and continue the fight, so the POW’s form an escape committee to manage the various attempts  -  but all is not what it seems.

What are the noises coming from the escape tunnel they are digging ?

Why do the guards only appear as shadowy outlines in the fog surrounding the camp ?

Why is there a cabin on the other side of the barbed-wire fence - and who is in there ?