This book written by Gordon Korman is the second book in the first 39 Clues series, The Clue Hunt. The main characters, Amy and Dan Cahill, are led by the hunt for the clues to Vienna, Austria, and then to Venice in search of the second clue. They are first attacked on the train ride to Austria by their meat-head cousins, next they are trapped in a cave-in by the mysterious "man-in-black." They find their way out, and along the way, find a parchment with German writing on it. It looked like a list of ingredients, the first clue was an ingredient, cannot be a coincidence.
While in Italy, they discover that their cousin--who is also in the hunt-- is there too, so they decide to follow him, and they end up in some sort of secret base. They find secret diary pages in the base, and steal them. The pages lead them to a deceased Italian music host's home. In the house there is a harpsichord, which has a big secret, but that can only be discovered by reading the book.
I would rate this book five stars because it has a lot of action and it is a mystery, which are my two favorite genres of books. I would recommend this book to people that like books that involve lots of action and has a great mystery.