How much longer Adriaan?

Bassie & Adriaan are in the French department, Brittany, in the old French pirate town, Saint Malo. There they will look for the package and if you are there on time they will also visit a castle, also known as Fort National. They searched everywhere in the castle, but no trace of the package, where could the package be?

Bassie & Adriaan decide to go back to the Netherlands without a package and decide to leave the castle, but then they expect an unpleasant surprise.