London 1826. Young socialite, Grace Baxter, will not marry old Lord Silverton with his salivary incontinence and dead-mouse stink. She is devastated to discover that she is a pawn in a business arrangement between slobbery Silverton and her calculating parents.
Refusing this fate, Grace resolves to stow away. Heading to the docks, disguised as a lad to ease her escape, Grace encounters smooth-talking naval recruiter, Gilly, who lures her aboard HMS Discerning with promises of freedom and exploration in South America.
When Grace’s big mouth lands her bare-bottomed over a cannon for insubordination, her identity is exposed. The captain wants her back in London but his orders, to chart the icy archipelago of Tierra del Fuego, forbid it. Lieutenant Seamus Fitzwilliam gallantly offers to take Grace off the fretting captain’s hands by placing her under his protection.
Grace must now win over the crew she betrayed with her secret, while managing her feelings towards her taciturn protector, whose obstinate chivalry stifles her new-found independence. When Grace disregards Seamus’ warnings about the dangers of the unexplored archipelago, it costs a friend his life and Grace realises she is not as free as she believes.