An 11-year-old puzzle master, Sam has always loved riddles, conundrums, and brainteasers. Though sharp as a tack, he often uses gut instinct to feel his way to an answer. He's quick on his feet, but sometimes his mouth gets a little ahead of him. At school, he's got a reputation as a bit of a troublemaker, though it's usually his loyalty to his friends and love of a challenge that lands him in hot water with the principal. He likes candy, comic books, and can't resist cracking jokes—especially when he's nervous.

With an inexhaustible thirst for American history and a photographic memory, 11-year old Marty is like walking, talking encyclopedia. Her intelligence and ferocious curiosity isolates her from other kids her age, who think she's weird. This makes her vulnerable and a bit shy, but also causes her to value friendship above all else.

At 13-years old, Theo is the strong, silent type. A levelheaded guy, Theo prefers to take the time to make a good decision rather than leap into action like Sam or assume that he knows everything like Marty. He is careful and serious because of the extraordinary legacy he is a part of, and the burden of his secret ancestry.

Tall, serious, and brilliant, Evangeline is in her mid-sixties. As an ancestor of Benjamin Franklin, it's her duty to keep the secrets of the Founders and their artifacts. She's willing to crisscross the country and enlist the help of the most unlikely of allies in order to keep the Republic safe.

A descendant of the infamous traitor Benedict Arnold, Gideon and his family have always resented the way history treated their ancestor. After discovering that the Founders have hidden an artifact of tremendous power, Gideon has become obsessed with taking it for himself. He plans to use its power to start a new revolution—one where he will be the country's greatest hero. He will stop at nothing—not even killing—to complete his mission.

With his craggy, sunbaked skin, the man looks like he was carved from stone, and indeed, he's just as tough. Cold, calculating, and absolutely ruthless, Flintlock is Gideon Arnold's faithful and formidable right-hand man. Flintlock believes in his mission, and he won't let some kids interfere with its success, even if that means he has to get his hands a little dirty along the way…