The Mysterious Benedict Society and the Perilous Journey
"Children you must not come STOP Dangerous. The Mysterious Benedict Society is back with a new mission: a mind-bending international scavenger hunt designed to test their individual talents. As they search for all the clues and riddles Mr. Benedict has hidden for them, Reynie, Sticky, Kate, and Constance face an unexpected challenge that will reinforce all the reasons they were brought together in the first place and require them to fight for the very namesake that united them. Join the Mysterious Benedict Society at your own risk!"
Summary from back of The Mysterious Benedict Society and the Perilous Journey (MT Books, may 2009 Edition)
The Mysterious Benedict Society and the Perilous Journey by Trenton Lee Stewart is more about how the 4 children have changed after their previous adventure. They have to try to save Mr. Benedict from Ledroptha Curtain but along the way you learn how each of them has changed. They have all regained/found their families. Their parents are always worried for their safety after their last adventure and in order to save Mr. Benedict they have to sneak away and go against their parents. All in all it was a really good book, I liked the first one a little more but it is definitely worth continuing the series. Rating: 5 stars
p.s. I'll post about the last book soon