Adapted from the 1943 short story Le Passe-Muraille by Marcel Aymé, it is set in Paris shortly after World War II and centers on a shy, unassuming clerk who develops the ability to walk through walls, and who challenges himself to stick to his moral center and change others' lives, and his own, as a result.
We are in Paris, in Montmartre, shortly after the second world war. It is morning. Our hero, whom we'll call Monsieur , is on his way to work. He is an ordinary civil servant, but very committed to his humdrum job, much more so than his rather grumpy colleagues. Dusoleiks unexciting life, however, is periodically irradiated by his beautiful neighbour, Isabelle. He lives for a glimpse of her. As he returns from work, we see her cross the square. Unbeknownst to him, despite her respectable marriage to a court official, her life is as banal and lonely as 's own. She is addicted to novels and magazines, and dreams of romance and intrigue. As evening falls we meet the other habitués of the square: a painter; a whore; a newsvendor; and the Prosecutor, Isabelle' husband, with two policemen in his pay.
On the way up his stairs curses at yet another power outage, a symptom of postwar austerity. When the lights come back on, he, to his astonishment, is not outside his flat, but in it. Whence has he acquired this mysterious gift of being able to pass through solid walls? He solicits medical attention. Clutching the pills the Doctor has prescribed, he returns home, choosing to ignore his newfound powers. His life may not be spectacular, but at least it's familiar. The next day, however, he is grossly insulted by his new boss and uses his gifts to wreak glorious vengeance.
Meanwhile, Isabelle is sad and lonely. Her plight is ignored by an uncaring husband who has his own private pleasures. now decides to use his powers to do good. Under the nom-de-crime of Passepartout, he begins his Robin Hood campaign by making a gift of diamonds to a rather dejected whore who is failing to attract the business she did during the war. may be able to walk through walls, but he still lacks the courage to declare himself to Isabelle. She, however, has turned her fantasies towards this Passepartout, her new hero. The Painter notices his secret passion and warns him against acting on it. Nevertheless, hatches a plan. He will break into the deepest vault of the Banque de Paris and set off the alarm, causing himself to be caught in flagrante. How will Isabelle be able to resist?.
In jail waits for Isabelle to visit him. The attention he actually attracts – from two of his female work mates – is much less welcome. Disgruntled, he walks through the wall and out of prison. Back in the square, he reveals himself to Isabelle. When she says she cannot leave her husband, decides to face up to his destiny and to stand trial for his crimes.
We are now in court. is represented by a nervous young lawyer, his only protection against the wrath of Isabelle's husband, the Public Prosecutor. The somewhat bizarre proceedings are interrupted by the appearance of Isabelle. She has an astonishing revelation: her husband was a Nazi collaborator in the war. He should be on trial, not . explains that everything he did, he did for love. And, this being France, he is pardoned. However, just as he is about to follow Isabelle home, he loses his nerve. The entreaties of the company, nonetheless, prevail, and our two lovers spend a night of passion together.
The next morning is awakened by the world press, all keen for him to display his powers for the cameras. He has a hangover–from love, from champagne, from everything. Looking for some aspirin, he finds the pills the doctor gave him. They provide the cure … not for his headache, but for his ability to walk through walls. As the pills take effect, is caught mid-leap and becomes stuck fast in a wall. One by one his friends arrive, and, led by Isabelle, the company laments what might have been.
Nevertheless, far from being an ordinary man, is remembered in song and fable. And to this day there is a statue in Montmartre of Le Passe-Muraille, the man who could walk through walls. And that is the only part of this story which is true …