In 1810, Lucy Bluecrowne, twelve, is bored living ashore with her stepmother and half brother until two nefarious strangers identify her little brother as the pyrotechnical prodigy they need for their evil plan.
Two English girls are on a quest to find the three pieces of a magical engine that can stop war, but after their ship is captured by the Americans who are fighting the War of 1812, the American midshipman who captured them is faced with a choice.