"Charlie Thorne must search for Charles Darwin's hidden treasure in South America--with plenty of enemies hot on her trail"--

When Greg and the Musketeers return to Paris and find the city under siege, they leap into action to prevent King Louis from being overthrown and history from being changed forever.

While on a mission aboard the The Emperor of the Seas, Ben Ripley faces off against his arch enemy, Murray Hill, on the high seas and quickly finds himself in hot water as things take a dangerous turn.

In Paris with his parents to sell family heirlooms, fourteen-year-old Greg Rich suddenly finds himself four hundred years in the past, and is aided by boys who will one day be known as "The Three Musketeers."

"Decades ago, Albert Einstein devised an equation that could benefit all life on earth -- or destroy it. Fearing what would happen if the equation fell into the wrong hands, he hid it. But now a diabolical group known as the Furies is closing in on its location. In desperation, a team of CIA agents drags Charlie into the hunt, needing her brilliance to help them find it first -- even though this means placing her life in grave danger. In a breakneck...