Jack Holborn is a 13-year-old boy living in an orphanage in late 18th-century Bristol.

He runs away in order to join the crew of the "Charming Molly", a privateering vessel commanded by Captain Sheringham.

Jack is desperately seeking answers to the mystery of his origins, and is not about to let the Captain off the hook.

Meanwhile, the judge Lord Sheringham, who hates his twin brother the privateer for the dishonour that his side dealings with pirates have brought on their family, plans to bring the Captain to justice.

Jack eventually manages to stow himself away on board the "Charming Molly," and the journey begins.