A dramatic game of cat and mouse in the picturesque streets of Arles - The fifth case for Captain Roger Blanc. November in Provence: Captain Roger Blanc has arranged a weekend in Arles with his secret lover, examining magistrate Aveline Vialaron-Allègre. They have chosen the city's Roman amphitheater as their meeting point. There, Aveline accidentally witnesses a cold-blooded murder. She narrowly escapes death herself, but the unknown perpetrator steals a bag containing important documents that she must present to her husband, the politically powerful Secretary of State, in Paris. Blanc and Aveline have only two days to find the murderer and retrieve the missing documents. However, no one must know they are in Arles, and no one can officially help them. Gradually, they discover that...