Time Traveler's Manuscript

When a leather-bound book containing the writings of a man from the previous century falls into the hands of Natalie and Levi, they aren't sure what to make of it. The mathematical equations, references to world-famous physicists, and strange symbols don't seem to have anything to do with one another until the kids begin to understand just how brilliant the author truly was. Suddenly, they find themselves in an adventure where they have more questions than answers, and nothing seems possible. How did Mrs. Marwood, the old woman who gave them the journal, get it in the first place? Who is following them, and why? As they race to uncover these secrets, they may end up discovering something even more mysterious, and far more dangerous.