The Alchemyst by Michael Scott

In The Alchemyst, twins Josh and Sophie Newman are living normal lives in San Francisco. Josh works at a bookstore run by the Flemings. Sophie works at the coffee shop across the street. One day, their lives change forever. The Flemings are actually the immortal Flemings, and the twins are the twins of legend.

I liked the plot, concepts and nuances of this book, but the writing and dialogue were...off. It also seems a little contrived, but overall it's a good series.