Saint-Malo National Fortress is a wartime detention site whose role becomes starkly visible during the siege of Saint-Malo: French prisoners are confined there, and a shell intended for another target kills nine of them. It also stands at the end of an occupation order that sends detained men from the city to the fortress at low tide, linking military confinement with the coercive control of civilian life.

A Place of Detention

The fortress holds three hundred and eighty Frenchmen against their will during the siege. Their confinement is precarious: they have minimal cover even as fighting and destruction spread through the surrounding city. The fortress is not merely a military landmark in these scenes but a place where civilians and prisoners are made vulnerable to the forces closing around Saint-Malo.

The site also enters the search for the Sea of Flames through the fate of Marie-Laure LeBlanc’s uncle. Reinhold von Rumpel believes the uncle was sent to the fortress and carefully searched before being taken there. He reasons that the man carried only his papers, not the jewel, narrowing the possibilities in von Rumpel’s pursuit without revealing what happened to the stone.

The Siege and the Shelling

On the third afternoon of the siege, the shelling briefly lulls while fires continue across the city. Around four o’clock, an American field howitzer two miles away fires a single shell that is improperly ranged. It passes over the city walls and strikes the fortress’s northern parapet, where the French prisoners are being held.

Nine prisoners are killed instantly. One had still been holding the hand of a bridge game when the shell struck. That small, ordinary detail sets the prisoners’ interrupted activity against the abrupt reach of the bombardment: even a brief lull offers no protection inside the fortress.

Destination of the Detained Men

As the occupation tightens its hold on Saint-Malo, an evacuation order is reported alongside the closure of the city gates. Every man between sixteen and sixty is to be detained, assembled at the tower of the château, and marched to Saint-Malo National Fortress at low tide. The order describes a sequence of custody and movement, turning the fortress into the prescribed destination for a broad group of the city’s men.

The planned march is distinct from the confinement of the three hundred and eighty prisoners already inside the fortress. Together, the two episodes establish its place in the siege as both an existing prison and an intended holding point for newly detained residents. Its narrative significance lies in that convergence: military danger and occupation policy meet at a site where people are confined, exposed, and separated from ordinary civilian life.