During the 1790s, on the Cornwall coast, local pirates led by Black John shipwreck ships during stormy nights and plunder their cargo.The pirates destroy the pilot lights and light misleading fires to guide the ships in distress towards their doom.The pirates kill the surviving sailors and then plunder the ship's cargo.The local magistrate, Squire Trevenyan is aware of Black John's ship wrecking and smuggling.But he's powerless since Black John knows the Squire's darkest secret and threatens to reveal it.Worse still , Squire Trevenyan's son, Christopher, falls in love with Louise Lejeune, the daughter of a local merchant whom the Squire doesn't approve of.During the day,a daring highwayman known as The Captain robs any stagecoach that ventures through his domain.Squire Trevenyan is under pressure to end the lawlessness in Cornwall.