Jupiter and his brother Patrick are about to embark on a merchant ship bound for home in Sierra Leone, but are set upon by a vicious Navy pressgang. The brothers are beaten, bound, imprisoned at bayonet point and finally marched to join a Royal Navy frigate, the Boneta. In word and deed, they are now prisoners of His Majesty King George. They have no idea where they are, or where they are heading. The Boneta is a ship full of secrets, and it's on a mission. Enemies are swiftly made, and the brothers can trust no one. Amid the mystery and danger, Jupiter will need all his strength and wits to survive - and, most surprisingly of all, some very strange and new technology. What they discover hidden in the holds of the ship will propel Jupiter and Patrick into an entirely unforeseen battle for their lives ...