In 1943, Dave (Stephen Boyd), an officer, and Jim (Tony Wright), escape from separate prison camps and are paired together by the Resistance. They are taken to Marseilles by a fishing boat captain to wait for the right opportunity to try for England. While they wait, local woman Lise (Anna Gaylor) falls in love with Dave. He is attracted to her, but is engaged. Meanwhile, Emile Blanchard (Eugene Deckers) refers those desperate to leave France to 'Dr.' Martout (James Robertson Justice), unaware that his associate is a serial killer who grows rich from his crimes. Given an ultimatum by his displeased superiors to do something about the French Resistance, the German military commander of the city decides to evacuate and demolish the crime-infested Old Quarter, where Dave and Jim are hiding, with only two hours warning. Dave wants to wait for the fishing captain, but Jim chooses to try Dr. Martout. When the captain does show up, Dave goes to fetch Jim, and rescues him from Martout's clutches. With buildings blowing up left, right and centre, the pair prepare to make their way to freedom....