Plymouth 1570; Ellyn Cooksley fears for her elderly father's health when he declares his intention to sail with Drake on an expedition he has been backing. Already yearning for escape from the loveless marriage planned for her, Ellyn boards the expedition ship as a stowaway.
Also aboard the Swan is Will Doonan, Ellyn's charming but socially inferior neighbour. Will has courted Ellyn playfully without any real hope of winning her, but when she is discovered aboard ship, dressed in the garb of a cabin boy, he is furious.
To Will's mind, Drake's secret plot to attack the Spanish bullion supply in the New World is a means to the kind of wealth with which he might win a girl like Ellyn, but first and foremost it is an opportunity to avenge his brother Kit, taken hostage and likely tortured to death by the Spanish. For the sake of the mission he supports Drake's plan to abandon Ellyn and her father on an island in the Caribbean until their mission is completed. But will love prove more important than revenge or gold?
Mistress of the Sea is an epic romantic adventure set against the backdrop of Francis Drake's first great enterprise - the attack on the Spanish 'Silver Train' on the isthmus of Panama