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.
When pirates get hold of a top secret document that could turn the tide between England and Spain, it falls to the dashing "Don Carlos" (Lex Barker) to use all his guile to procure the parchment. What now ensues here is actually quite watchable, but really basic and entirely forgettable. Walter Barnes stands out as "Calico Jack" but otherwise the remainder of the cast present us with little better than a join-the-dots maritime adventure that does feature the odd, entertaining, action scene but for the most part is all pretty procedural. Given the budget can't have been much, the production is fine with the costumes and sets doing what was required - but Barker should just have stuck to swinging through the trees in a loin-cloth and Nadia Marlowa's shockingly wooden "Leonora" could easily have been his "Jane". I didn't hate it - I do like the genre, but the poor dialogue and constantly reprised refrains from Gino Filippini's unremarkable score didn't really help this stand out. The title holds out much too much promise for this mediocre film, sorry.