Twelve-year-old Marco Loristan has spent his life moving from place to place with his father, Stefan, always hiding their heritage. Their home country of Samavia has been in turmoil ever since the king was overthrown five hundred years ago, and now its people are forced to fight in the armies of warring factions. But legend has it that the heir of the true king escaped, and his descendant is waiting until the time is right to reclaim the throne and restore peace to the country.

While living in London, Marco learns of a secret his father has been hiding: Stefan knows the identity of the lost prince and that he'll reveal himself soon. But they have to spread the word to the prince's supporters. And to do that, they'll need a messenger who can escape the notice of the current ruler's spies--someone like a young boy.

With the help of an orphan he befriends in London, Marco is tasked with traveling across Europe to share the news, preparing the way for the lost prince to return.