Bresson's A Man Escaped, like The Trial of Joan of Arc, is closely based on factual records. Yet it is far from being a documentary. 'I would like to show this miracle', Bresson explains. 'An invisible hand over the prison, directing what happens and causing such and such a thing to succeed for one and not another. The Spirit breathes where it will.'

The story is taken from Andre Devigny's account of his imprisonment by the Gestapo for his activities with the French Resistance movement during the German occupation. Devigny managed to escape from Fort Montluc in Lyons just a few hours before he was to have been executed. The film's Devigny is Fontaine.

First we see Fontaine being transported to the prison; he makes an ineffectual attempt at escape. In his cell he is entirely alone. By intense concentration on the objects around him, he begins to devise a means of escape. He transforms a spoon into a knife with which he dismantles the cell door; blankets are woven into ropes; lanterns used for hooks. Gradually, he comes into contact with other prisoners who help him. Coincidence, or fate, saves Devigny on several occasions from being discovered.

Another prisoner, Orsini, attempts to escape, but is killed in the process. Fontaine observes this dispassionately and works out improvements in his plan. Then, he is interrupted by the arrival of a cell-mate, Jost, who demands to be taken along. As it turns out, Jost's assistance becomes a vital factor in their successful escape.