A secret document has fallen into the hands of pirates. Spain and England are both interested. The English commissioned a notorious pirate and the Spaniards procure their best officer, Carlos de Herrera, to retrieve the document for them.

Luis de Monterey is a ship captain who is pitted against a crafty pirates.

Sword in the Shadows (Italian: Una spada nell'ombra) is a 1961 Italian swashbuckler film directed by Luigi Capuano and starring Tamara Lees and Livio Lorenzon.