Sam's eyes were on the clock: 9:54.
- opening line
In this series, Sam and Martina use their brains and skills to solve puzzles that will help find an invention that could save or destroy our nation. After winning a contest, they are on a trip across the country, but it quickly turns into something far more important and dangerous. The founding fathers left clues to seven "keys" that will unlock Benjamin Franklin's greatest invention, but, sinister forces are also searching for the keys. Sam and Martina get along like oil and water, but they must learn to work together to solve the difficult puzzles and avoid booby traps to find the keys first.
In this book (the first in the series), Sam and Martina are looking for Ben Franklin's key. Throughout the book, we learn different facts about Franklin (thanks to Martina's vast knowledge). Most of the story takes place underground as the kids evade the bad guys and try to survive the dangerous puzzles/traps. The keys are vitally important and failing to solve the puzzles could lead to death. Sam and Martina didn't sign up for this, but they are determined to find the keys and thwart the bad guys.
This is a fun adventure/mystery story. Kids who enjoy solving puzzles or have an interest in history will love this book. There are three books in the series so far, but I'm assuming there will eventually be seven (for the seven keys). The keys are not all literal keys like Ben Franklin's key - each one relates to the founding father who hid it. The second book to Thomas Jefferson's Eagle's Quill, and the third to Alexander Hamilton's Ring of Honor.
Recommended to: Ages 9-13, fans of history and adventure stories.