The Mistress and the Key by Ben Mezrich takes place immediately after the events of his book, The Midnight Ride.

"Hailey and Nick have just uncovered one of the biggest secrets of the Revolutionary War. Now they find themselves in Philadelphia - looking at connections between Paul Revere and Benjamin Franklin. The more they discover, the more shocking the implications become. There are some who want to keep the secrets buried - and will do anything to keep it that way."

Do you like a Dan Brown story? Taking historical figures, events and monuments and inventing a wild story about what really happened? You'll love this. Lots of famous people here, including Mozart and Gustav Eiffel. I never knew Eiffel's connection to the Statue of Liberty. Hailey and Nick continually race around and find more stuff. The action seldom lets up. The Family is a great bad-guy - almost a Bond-level villain.
Thought this was better than the last book. Lots of crazy action in this one.

An unlikely pair searches for a secret hidden within history

Hailey Gordon was working her way through a graduate level mathematics program at MIT using her skills with numbers to rack up wins at casinos. Nick Patterson was a street=smart thief recently released from a stint in prison who was trying to fence artwork from an infamous museum heist in Boston of years ago. Their paths crossed by accident (Hailey was evading casino security at the time), and decided to join forces in offloading the paintings. That decision has led them into a search to find a secret from Revolutionary War times that, if it proves true, could upend much of what people believe about that period in history. In this, the second stage of their quest (after the events that unfolded in author Ben Mezrich’s previous novel, The Midnight Ride), the pair is still dodging FBI Special Agent Zack Lindwell, who suspects that the trail of apparently missing art they are leaving behind is not the straight-out theft that it appears to be, as well as members of a shadowy group known as The Family, who have demonstrated that they have no problem with killing to get their hands on what Hailey and Nick are tracking down. With the help of history professor and noted expert on Paul Revere, Adrian Jensen, the path leads from Mr. Revere to Ben Franklin, from Boston to Philadelphia to New York, and will weave elements like the Liberty Bell and alchemy into the story along the way. Can they find out what it was that Revere, Franklin and others seem to have left behind for later generations to pursue before either the FBI and/or the Boston PD throw them in prison or The Family (and the mysterious woman known only as The Heiress) catches up to them, and removes them from the trail…permanently?
When I read the initial synopsis of this thriller, it immediately brought to mind the Cotton Malone series by Steve Berry and the Pendergast books by Lincoln Child and Douglas Preston, both of which are terrific series that combine twisty plots, quirky bits of history, and intriguing characters to provide a terrific read, with perhaps a dash of Dan Brown. The concept of this new series could prove similarly enjoyable, but in the end the storyline didn’t grab my interest in the same way. Having grown up and gone to college in the Boston area (thanks to the author for the shout out for my alma mater, Tufts), the setting and history were certainly ones with which I was quite familiar, and I was intrigued to see what might be made of them, but the characters felt a little flat and the plot just sort of chugged along. Those who have read the first book in the series will realize that, just as the end of that book was not the end of the quest, the culmination of the events in this installment is also only the end of this stage of the quest (which will continue along in the next book, it would seem). I found this to be a somewhat enjoyable read, neither horrible nor terrific. There are plenty of interesting tidbits about Ben Franklin’s accomplishments among other things, and new historical figures find their way into the mix as well. My thanks to NetGalley and Grand Central Publishing for allowing me early access to The Mistress and the Key.