When Grace Cahill died, she left her heirs a choice: one million dollars in cash, or the first clue in a chain that leads to the source of their family's power. Amy and Dan, Grace's favorite grandchildren, choose the clue and set off on a dangerous adventure where they must compete with their relatives to solve the mystery. 
 As a kid, I loved stories like this, from the Newbery winning The Westing Game to the awful 80's film Midnight Madness. I would have been totally sucked in by this series of books with accompanying web site, trading cards and contests. 
 The first book focuses on Benjamin Franklin (apparently a member of the Cahill family) as the children must research him to solve his puzzles and figure out where to go next, while their cousins creep after them and try to steal the fruits of their effort. 
 This was a quick, fun, fluffy read, but I'm not sure I'll continue reading the series. I've been enjoying Rick Riordan's YA books, but I am not familiar with the authors who wrote the following books, which makes it sound more like a franchise than a coherent story. It's a good thing The Throne of Fire is waiting for me at the library!