In October 1940, while sailing across the Atlantic, a Belgian vessel disguised as a merchant ship opens fire on the submarine Cappellini of the Italian Royal Navy. A brief but fierce battle ensues in which the Italian submarine sinks the enemy ship with gunfire. And it is at this point that the commander takes a decision that will go down in history: to rescue the twenty-six members of the Belgian crew from drowning in the middle of the ocean and tow their lifeboat to the nearest safe port, as required by the law of the sea.