An important meeting of French resistance leaders is broken by the Germans. Anne-Marie Poitiers, code-name "Nina", escapes and seeks help from "Vincent", a British agent operating from the town of Bracieux. His instinct is to kill her, together with an RAF pilot who has crashed in the area, because both are security risks. But London orders otherwise, and the three set off on their hazardous and dangerous escape to England.
Nina witnesses the rape of a farm-girl by a Vichy policeman. Disgusted by the lack of sympathy shown by Vincent and Jimmy, she runs away and is hidden by a farmer.Vincent and Jimmy abandon their plans and begin to search for her, but they fall into the hands of Communist Maquis who believe thay are Gestapo.Nina arrives and proves their true identity, but the Communists will only let them go as a decoy for the Germans who are searching the area.
To escape the Gestapo closing in on them, Vincent takes Jimmy and Nina to his family chateau where they are hidden by a loyal gamekeeper.
Vincent, Jimmy and Nina hide in a disused room at the top of Vincent's family chateau. But their refuge becomes a prison when the Gestapo occupy the lower rooms.
Vincent, Jimmy and Nina have 50 miles of occupied France to traverse before they reach the River Cher where Free France begins.
The three arrive late at night at a safe house where they are expecting to receive help, but instead find it empty and apparently abandoned in a hurry. Vincent becomes suspicious of Jimmy, insisting he hand over his identity discs to prevent him from taking the easy way out of handing himself in as a shot-down airman; Nina secretly removes them from his pocket. Jimmy goes outside to have a look around, Nina and Vincent hear shooting from the town and are preparing to leave when Jimmy returns, warning them that the Germans are starting to search house-to-house and they...
While the German military roars south to Toulon, Vincent, Jimmy and Nina hide in an old toll house. But Vincent imperils their lives by trying to contact the local Resistance, and Nina cracks up under the strain.
Jimmy and Nina shelter at a farmhouse. At once they realise they've walked into a bizarre and sinister situation...
Sergeant Gratz of the German Intelligence closes in on Vincent, Jommy and Nina, who are hiding in a factory which manufactures arms. One of the workmen is an informer. But which one?
Sergeant Gratz begins to interrogate Nina. His methods are persuasive. Lutzig wants her information as well, and the two men become involved in conflict of authority between the SS and Abwehr.
Three important villagers are taken as hostages and used as ransom for the fugitives.
A sleazy nightclub becomes the focal point for the Resistance and for the French collaborators. Vincent, Nina and Jimmy find it more dangerous to hide - and decide to go on display in front of the SS who have caught up with them.
Jimmy and Vincent learn of an impending raid by SS troops on a Bordeaux junk shop where a meeting of Resistance leaders is to take place. They are unable to warn the Maquisards, and decide to visit the shop...with tragic results.
Jimmy is sheltered by a French Resistance girl after he narrowly escapes the SS round-up in which Vincent was caught. But the girl's young brother has been brainwashed by Nazi propoganda and is a potential informer.
Gratz captures a young British agent who has been landed from the sea to penetrate a Bordeaux war factory. He decides to exploit Nina's attraction for the agent in order to extract information from him. But the agent is wary of Gratz's offer.
Gratz hides Cadet in his flat, both from the SS attempting a house to house search and his own CO, Colonel Reichwein, who now has his own doubts about Gratz. Cadet plans to leave and take Nina with him, but realises this will be impossible when Gratz deliberately lets slip that Nina knows vital information, and the SS is on the alert for any escape of hers. Cadet attempts to kill Nina instead, but merely reveals his intentions - the gun he uses is unloaded; getting into a struggle with Gratz, he is then killed himself by Nina.
Jimmy, posing as a Flemish seaman, is drafted into the German-controlled metal works in Bordeaux, where he makes an important discovery.
Nina and Adelaide rendevous in the Church of St. Xavier. Was it a ruse to get Nina away from Gratz or, even more sinister, was it master-minded by the Gestapo?
n Paris, Vincent is offered his freedom, but can he be sure that a trap is not being set for him?
A Gestapo agent in the metal works terrorises Jimmy into revealing his identity - and an innocent Polish worker is executed.
The Abwehr capture SOE radio operator Diana Maxwell, who is interrogated by Gratz with the hope of turning her as a double agent. Gratz is already operating Cadet's radio, in the flat next to his, using Private Voigt as a radio operator. He inadvertently lets slip to Nina what is going on, and she blackmails him to do as she asks in return for not informing Gratz. Diana appears to cooperate with Gratz and is installed in the flat, but Nina is able to collect genuine messages from Anton to be sent instead. Diana is able to inform London of the scheme.
Vincent, Jimmy and Adelaide infiltrate the German-controlled metal works.
Vincent, Nina and Adelaide embark on a highly dangerous railway journey.
Lutzig has finally arrested the little man and he is now at the mercy of the SS. They subject him to all sorts of physical and mental tortures to force him to betray Nina. Gratz, however, is equal to almost anything Lutzig can hand out but he finds himself confronted by someone he didn't expect...his wife! This shatters him but he manages to survive and make a deal with Lutzig.
Through the resistance, Gratz is able to meet Vincent, Jimmy and Nina. He offers to help them escape, using Cadet's radio and code to contact London and arrange a pick-up, knowing that his transmissions can be detected by the SS. The offer is accepted and a rendezvous on the coast organised, but Vincent has decided to stay in France and return to his network. After sending Jimmy and Nina outside to their car, Vincent intends to kill Gratz, but instead after a struggle Gratz shoots and kills Vincent. Outside, Jimmy and Nina hear only the shots and know they must go on ...
Encouraged by Gratz and helped by the Resistance, Nina, Jimmy and Adelaide reach the coast to escape to England - but the SS are waiting for them.
